Characteristics of Perpetrators in Homicide-Followed-by-Suicide Incidents: National Violent Death Reporting System—17 US States, 2003–2005 — (American Journal of Epidemiology)

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SSRI Stories Editor’s Note:   This study was conducted based on data from the U.S. National Violent Death Reporting System, part of the Centre for Disease Control and Prevention.  The information is intended to:  “provide states and communities with a clearer understanding of violent deaths”.  Despite this, its section on Risk Factors for Suicide makes no mention of psychoactive and other drugs as potentially predisposing people to suicide risk, despite the fact that they may be the single biggest risk factor.   

This study happened to include use of antidepressants, not because the authors had any intention of linking the drugs to violent acts, but because they did want to link murder-suicides to mental illness, and use of antidepressants was viewed as seeking treatment  and therefore an indication of mental illness.

This study is interesting because of what it does not examine.  Of the 408 perpetrators in the time period of interest, toxicology tests were done on 145 (36%).  By far the largest group of perpetrators were men killing intimate partners.  However, there were 33 filicides, that is, parents killing children. Of these, toxicology tests were done on 11 people. Of the 11, 4 showed the presence of an antidepressant. Seven people were known to be receiving mental health “treatment” including the 4 taking antidepressants.

Also, the number of people who had been taking antidepressants which were not still present in their blood at the time of death is not known.  This could include people in withdrawal from antidepressant use. Of the 33 people who killed their children, it is known for sure that 4 were on antidepressants, 3 had no antidepressants in their blood when they died, and there is no information about whether or not the other 22 were taking these or other drugs. 

American Journal of Epidemiology

American Journal of Epidemiology Published by the Johns Hopkins Bloomberg School of Public Health

Nov 1, 2008

Authors:

1.    J. Logan,

2.    Holly A. Hill,

3.    Michele Lynberg Black,

4.    Alex E. Crosby,

5.    Debra L. Karch,

6.    Jamar D. Barnes and

7.    Keri M. Lubell

Correspondence to Dr. Joseph E. Logan, Division of Violence Prevention, National Center for Injury Prevention and Control, Centers for Disease Control and Prevention, 4770 Buford Highway, MS-F63, Atlanta, GA 30341 (e-mail: ffa3@cdc.gov).

Received January 22, 2008.

Accepted June 17, 2008.

Abstract

Homicide-followed-by-suicide (referred to as “homicide-suicide”) incidents are rare events but can have a profound impact on families and communities. A better understanding of perpetrator characteristics and how they compare with those of other homicide suspects and suicide decedents might provide insight into the nature of these violent acts. This report is based on 2003–2005 data from 17 US states participating in the National Violent Death Reporting System, a unique, incident-based, active surveillance system that integrates data on violent deaths from multiple sources. Of the 408 homicide-suicide incidents identified, most incidents were committed with a firearm (88.2%) and perpetrated by males (91.4%), those over 19 years of age (97.6%), and those of white race (77.0%); however, just over half of filicide (killing of children)-suicides (51.5%) were perpetrated by females. Over 55% of male homicide-suicide perpetrators versus 26.4% of other male suicide decedents had prior intimate partner conflicts (P < 0.001). In fact, having a history of intimate partner conflicts was even common among homicide-suicide perpetrators who did not victimize their intimate partners. Recognition of the link between intimate partner conflicts and homicide-suicide incidents and strategies involving collaboration among the court/legal and mental health systems might prevent these incidents.

Some studies have proposed typologies for categorizing these incidents to help guide future research into this phenomenon (3, 6). These typologies are typically based on the victim-perpetrator relationships and generally include the following, by order of commonality: intimate partner-related homicide-suicide incidents (approximately 42%–69% of homicide-suicide incidents); familicide (killing of all family members in a household) or filicide (killing of children)-suicide incidents (18%–47% of homicide-suicide incidents); and extrafamilial homicide (killing of nonfamily members)-suicide incidents (12%–26% of homicide-suicide incidents) (1, 7). Some incidents are also of mixed type, where there are familial and extrafamilial victims involved.

Several studies have evaluated homicide-suicide incidents within selected populations (e.g., among the elderly) (8), in individual states (7, 9–12), and across multiple cities (13) and other countries (14–16). Few population-based studies on homicide-suicide incidents from multiple states are available in the literature. Using 2003–2004 data from the National Violent Death Reporting System, Bossarte et al. (2) estimated that only 11% of homicide-suicide perpetrators have a documented mental health condition and that approximately 30% are intoxicated at the time of the incident. Over 85% of perpetrators were male, and more than 70% were non-Hispanic white. Additionally, over 70% of victims in homicide-suicide incidents were female, and over 55% of victims were current or former intimate partners. Approximately 20% of victims are the perpetrator’s children, stepchildren, or other relatives. Approximately 80% of homicide-suicide incidents occurred in either the victim’s or perpetrator’s home, and over 80% were committed with a firearm. These findings were similar to those from earlier studies (7, 9–12, 17–21).

Circumstances leading up to these violent events have also been described in several studies. These include estrangement associated with divorce or breakup (1, 3, 10, 11, 13, 14, 17), real or perceived infidelity (1, 3, 14), mercy killing or death pact (2, 3, 22), and loss of employment or financial problems (2). Some events are also likely to be idiosyncratic of a perpetrator’s delusions or psychopathology (5, 23).

Although previous studies have expanded our knowledge about the characteristics of homicide-suicide incidents, many areas require further exploration. For example, there is little information comparing perpetrator characteristics across types of homicide-suicide incidents (typology based on the victim-perpetrator relationship). Similarly, there is little information available with respect to how characteristics of homicide-suicide perpetrators compare with those who commit homicide alone or those who commit suicide alone. Such information may lead to an increased understanding of etiologic factors related to the perpetration of homicide-suicide incidents (1, 3) and may inform the development of prevention and intervention efforts.

The primary objective of this study was to describe perpetrators across a full range of homicide-suicide incidents that occurred within a multistate, population-based surveillance system. Additionally, we compared homicide-suicide perpetrators with other suicide decedents and with other homicide suspects to assess differences and similarities. To the authors’ knowledge, no study to date has had sufficient samples to do this kind of analysis by use of multiple data sources

MATERIALS AND METHODS

Data source

The National Violent Death Reporting System (NVDRS) is an incident-based, violent death surveillance system that combines data from multiple sources. Data collection for the NVDRS began in 2003 in 7 states (Alaska, Maryland, Massachusetts, New Jersey, Oregon, South Carolina, and Virginia). In 2004, 6 states were added (Colorado, Georgia, North Carolina, Oklahoma, Rhode Island, and Wisconsin). In 2005, 4 states were added (California, Kentucky, New Mexico, and Utah), bringing the total (as of 2008) to 17 states. Data collection is statewide with the exception of California, which collects data in only 4 counties (Los Angeles, Riverside, San Francisco, and Santa Clara).

Information is gathered from participating states on all suicides, homicides, legal intervention deaths, unintentional firearm deaths, and deaths for which the manner is undetermined (24, 25). The NVDRS includes information on the victims of violent death, the suspected perpetrators and their relationships to the victims, the involved weapons, and the circumstances leading up to the injury event (24, 26). Data from coroner and medical examiner reports, toxicology reports, various law enforcement records, supplemental homicide reports, and death certificates are linked into a single data repository. Several optional reports can also be linked into the data set, depending on the states’ preferences. These include crime lab reports, firearm trace reports from the Bureau of Alcohol, Tobacco, and Firearms, and child fatality reviews. Such integrated data provide greater insight into the nature of violent deaths than does any single data source (24).

States manage data collection typically through state health departments or a subcontracted entity, such as a medical examiner’s office. Data are gathered and coded by trained abstracters in each state. Data may be extracted from various reports or imported electronically from other systems (i.e., Bureau of Vital Statistics’ death certificate files or medical examiner’s data sets). All data are reviewed by the abstracter to ensure accuracy of the codes (27). To maintain consistency among abstracters, each abstracter follows a strict NVDRS coding manual. Additionally, for quality control purposes, 10% of all narratives are reviewed by staff of the Centers for Disease Control and Prevention to ensure accurate coding of circumstances preceding the violent death. The NVDRS has been described in further detail elsewhere (24, 27).

Case finding

The data used for this analysis represent the calendar years 2003–2005. Case identification was conducted from an NVDRS database that was updated through June 2007. Homicide and suicide incidents were identified by the manner of death recorded from the death certificates. Homicide-suicide incidents were defined as suicide incidents where the perpetrator committed at least one homicide within 1 calendar day prior to his or her suicide death. Incidents were categorized as homicide-suicide, homicide-only, or suicide-only incidents.

The homicide-suicide incidents were further categorized on the basis of the victim-perpetrator relationship. Information on the victim-perpetrator relationship was obtained from the narratives of the law enforcement, coroner, and medical examiner reports. In general, these narratives are based on information gathered from the victim’s neighbors, friends, family members, and other acquaintances.

Between 2003 and 2005, there were 420 homicide-suicide incidents, 20,188 suicide-only incidents, and 5,932 homicide-only incidents where 1 perpetrator is reported (homicide-only incidents were excluded if the perpetrator was either unknown (n = 2,388) or the incident had multiple perpetrators (n = 1,516)). It should be noted that information regarding trial results and convictions of suspected perpetrators is not included in the NVDRS. Therefore, in the remainder of this report, the term “suspects” is used, which includes both perpetrators and “suspected” perpetrators.

Of the 420 homicide-suicide incidents identified, the victim-perpetrator relationship could not be identified in 12 incidents; therefore, these incidents were excluded from this study. For the remaining 408 homicide-suicide incidents, 304 (74.5%) involved current or former intimate partners (this included spouse, former spouse, girlfriend, boyfriend, former girlfriend, and former boyfriend). There were 33 (8.1%) filicide-suicide incidents; these included child, stepchild, and foster child (child of the suspect, including both young and adult children). Additionally, there were 29 (7.1%) “other” family-related homicide-suicide incidents (including parent, sibling, grandchild, grandparent, in-law, stepparent, child of suspect’s boyfriend or girlfriend, intimate partner of suspect’s parents, foster parent, other family member) and 42 (10.3%) extrafamilial homicide-suicide incidents (babysitter, acquaintance, friend, roommate, current or former coworker, rival gang member, other person known to victim, or stranger).

Intimate partner-related homicide-suicide incidents were further divided into 2 categories, those with only intimate partners (n = 280, 68.6% of total incidents) and those with intimate partners and one or more additional victims (n = 24, 5.9% of total incidents). For the majority of the intimate partner-related incidents that had other victims (n = 16), the additional victims were children. For 8 incidents, the additional victims were friends, strangers, or other family members.

Analysis

Homicide-suicide perpetrators were compared across the various types by calculating frequency distributions of demographic factors (i.e., age, sex, race, and ethnicity) and various health-related and preceding life-event circumstances known to be risk factors for suicide and/or homicide (all health-related and circumstance information was gathered from the narratives written in the various law enforcement and coroner and medical examiner reports). These factors included having a current mental health condition, having a history of substance abuse problems, being suspected of intoxication at the time of the event, having a history of suicide attempts, having serious physical health problems (e.g., chronic pain or cancer), having a history of intimate partner conflict, having a history of other relationship problems, and having job or financial problems (28–31). Comparisons were also made regarding whether the perpetrator disclosed suicide intent (indicating signs of premeditation), whether the perpetrator was receiving mental health treatment (i.e., currently in mental health treatment or using antidepressants), and whether the perpetrator committed the act out of the belief that he or she was relieving some form of suffering (i.e., mercy killing). Because cell sizes were often small, Fisher’s exact tests were used to assess statistical significance for all categorical variables. The significance of observed differences in median age across the subtypes was evaluated by the Kruskal-Wallis test.

Perpetrators of homicide-suicide incidents were also compared with those who only committed suicide and those who only committed homicide. This analysis was stratified by sex, because male and female perpetrators often have different characteristics and preceding circumstances (3). For this analysis, 3 homicide-suicide perpetrators, 5 suicide decedents, and 843 homicide suspects were excluded because the sex of the perpetrator was unknown. Bivariate analyses using Fisher’s exact tests and a Wilcoxon test were conducted to assess significant differences in demographic variables.

Odds ratios were used to compare homicide-suicide perpetrators with other suicide decedents on the basis of the same health-related and life-event circumstances listed in the previous analysis. Because the NVDRS is a violent death surveillance system, less information is available with respect to the characteristics of suspected perpetrators who are still living. Therefore, we were unable to compare homicide-suicide perpetrators with homicide-only suspects with respect to these factors. Multivariable logistic regression analysis was used to calculate adjusted odds ratios; each model adjusted for age and racial/ethnic differences in order to make the two groups more comparable. Fisher’s exact tests and the Wilcoxon test were conducted by using the SAS for Windows 9.1 statistical package (SAS Institute, Inc., Cary, North Carolina). The multivariable logistic regression analyses were conducted by using the Stata/SE for Windows 10.0 statistical package (StataCorp LP, College Station, Texas).

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RESULTS

The demographic characteristics of the homicide-suicide perpetrators, stratified by homicide-suicide type, are presented in Table 1. Overall, perpetrators were mostly male (91.4%), over 19 years of age (97.6%) (median age, 43 years), of white race (77.0%), and of non-Hispanic ethnic status (89.5%). Most homicide-suicide perpetrators (64%) were aged between 20 and 49 years, ranging from 76.2% of the extrafamilial homicide-suicide incidents to 61.4% of the intimate partner-only homicide-suicide incidents. However, a high proportion (37.1%) of intimate partner-only homicide-suicide perpetrators were 50 years of age or older.

Characteristics of Perpetrators in Homicide-Followed-by-Suicide Incidents: National Violent Death Reporting System—17 US States, 2003–2005

Table 1.

Demographic Characteristics of Homicide-Suicide Perpetrators, National Violent Death Reporting System, 2003–2005

Table 1.

Demographic Characteristics of Homicide-Suicide Perpetrators, National Violent Death Reporting System, 2003–2005

Among incidents with male perpetrators, the vast majority of victims were female intimate partners (77.7%); 4% were children. In contrast, the victims of female homicide-suicide perpetrators were most likely to be children (48.6%); 40% of victims were male intimate partners. Thus, over half (51.5%) of the filicide-suicide incidents were committed by female perpetrators.

The majority of homicide-suicide incidents (>85%) were committed by perpetrators that were not suspected of being in a depressed mood or having a mental health condition by family members or friends. However, a third of filicide-suicide perpetrators were reported to be depressed or to have a current mental health problem (Table 2). Furthermore, for all types of homicide-suicide incidents, the majority of the perpetrators did not have prior reports of alcohol or substance abuse problems, a history of suicide attempts, or physical health problems. However, with the exception of the filicide-suicide perpetrators, about 1 in 5 perpetrators was suspected of being intoxicated at the time of the incident.

Characteristics of Perpetrators in Homicide-Followed-by-Suicide Incidents: National Violent Death Reporting System—17 US States, 2003–2005

Table 2.

Perpetrator Health Characteristics, Mental Health Service Use, Primary Weapon Used, and Life-Event Factors, National Violent Death Reporting System, 2003–2005

↵^a The results pertain to those with toxicology reports (i.e., intimate partner only = 96; intimate partner + other = 9; filicide = 11; other familicide = 10; extrafamilial = 16).   Ed – total = 145

Table 2.

Perpetrator Health Characteristics, Mental Health Service Use, Primary Weapon Used, and Life-Event Factors, National Violent Death Reporting System, 2003–2005

Only 4.9% of the homicide-suicide incidents were believed to have been the result of a mercy killing (Table 2). Of the 20 homicide-suicide incidents that were precipitated by this circumstance, 19 (95%) of them involved an intimate partner.

Approximately 10% of the perpetrators were currently in mental health treatment at the time of committing the homicide-suicide incident; the highest proportion (21.2%) was among those who committed filicide-suicide incidents (Table 2). Furthermore, for those with toxicology reports, a high proportion (36.4%) of the filicide-suicide perpetrators were found to be on antidepressant medications, suggesting that they had previously sought treatment for clinical depression or another mood disorder.

The most common weapon used by homicide-suicide perpetrators, regardless of the victims involved, was a firearm (Table 2). In general, 88.2% of homicide-suicide perpetrators, ranging from 72.7% of filicide-suicide perpetrators to 97.6% of extrafamilial homicide-suicide perpetrators, used a firearm to commit the violent act.

With the exception of the other-family-related type of homicide-suicide incidents, intimate partner conflict was the most common preceding life-event factor among perpetrators (53.9%) (Table 2). In addition to the intimate partner-related homicide-suicide incidents, these problems were also common among filicide-suicide perpetrators (36.4%) and extrafamilial-related homicide-suicide perpetrators (35.7%).

Demographic characteristics of homicide-suicide perpetrators were compared with those of suicide-only decedents and homicide-only suspects (Table 3). An estimated 92.1% (n = 373) of homicide-suicide perpetrators were male, compared with 78.2% (n = 15,793) of suicide-only decedents and 89.7% (n = 4,569) of homicide suspects. For both males and females, approximately 60% or more of the perpetrators were aged between 20 and 49 years across all groups (homicide followed by suicide, suicide only, and homicide only). A significant proportion of male homicide-suicide perpetrators and suicide-only decedents were aged 50 years or older (33.2% and 37.9%, respectively). Compared with male homicide-suicide perpetrators, a higher proportion of male homicide-only suspects were aged 10–19 years. This same pattern was observed for females. Similarly, for both male and female perpetrators, the vast majority of homicide-suicide perpetrators and suicide-only decedents were white non-Hispanics. Male and female homicide-only suspects were more evenly distributed among white (29.2%), black (47.4%), and other races (21.3%). However, for male homicide-only suspects who victimized an intimate partner, the distribution by race differed in that 40.2% were white and 39% were black (data not shown).

Table 3.

Demographic Characteristics of Homicide-Suicide Perpetrators, Other Suicide Decedents, and Other Homicide Suspects, National Violent Death Reporting System, 2003–2005

Table 4 compares the health, mental health, and life-event factors of homicide-suicide perpetrators with those of suicide-only decedents. Compared with males who died by suicide, male homicide-suicide perpetrators were significantly less likely to have reports of depressed mood, mental health problems, alcohol or substance abuse problems, a history of suicide attempts, physical health problems, mental health treatment, or job or financial problems or to have disclosed intent. They were significantly more likely to have a history of intimate partner conflicts. Further analysis of the 208 male homicide-suicide perpetrators who had a history of intimate partner conflict revealed that 191 (92%) of these perpetrators used a firearm in the homicide-suicide incident (Appendix Table 1). Furthermore, 75 (39.3%) of these 191 perpetrators were believed to have retaliated in response to a divorce request or breakup. In addition, 14 (7.3%) of these 191 perpetrators were currently in mental health treatment, and 34 (17.8%) were currently or recently in court for family-related issues (i.e., divorce, custody, child support) or were recently issued a restraining order.

Table 4.

Characteristics of Homicide-Suicide Perpetrators Versus Other Suicide Decedents, National Violent Death Reporting System, 2003–2005

When compared with female suicide-only decedents, female homicide-suicide perpetrators were less likely to be intoxicated at the time of the incident and less likely to have a prior history of suicide attempts. However, the 2 groups were similar in that a large proportion of female homicide-suicide perpetrators were identified as being in a depressed mood (28.6%), currently having a mental health problem (42.9%), currently being in treatment for a mental health condition at the time of the incident (31.4%), and having a history of intimate partner conflict preceding the incident (34.3%) (Table 4).

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DISCUSSION

Similar to previous research, this study found that most homicide-suicide incidents were perpetrated by white males in middle to late adulthood. Also consistent with previous research, this study found that most homicide-suicide incidents were committed with a firearm (2, 7, 9–11, 17, 20), the majority of victims were either current or former intimate partners, and a substantial number of victims were children (2, 9, 10). We also found that having a history of intimate partner conflict was highly common among most homicide-suicide perpetrators, even those who did not victimize their intimate partners in the homicide-suicide incident (e.g., extrafamilial homicide-suicide and filicide-suicide incidents). Our findings also suggest that homicide-suicide perpetration, particularly by males, is mostly preceded by intimate partner conflicts/violence as opposed to other determinants of suicidal behavior.

Although the demographics of homicide-suicide perpetrators, in general, differed from those of other homicide suspects, the demographics of males who perpetrated intimate partner-related homicide-suicide incidents were more similar to those of male suspects in intimate partner homicides. In addition, circumstances surrounding many of the intimate partner-related homicide-suicide incidents were similar to those of intimate partner violence (e.g., divorces or separations) (32). Primary prevention of intimate partner violence (preventing violence before it starts) using promising, effective strategies is an important step toward reducing the occurrence of homicide-suicide incidents and the violent deaths of intimate partners, children, family, friends, and even strangers that are associated with these incidents. Such strategies include changing social norms, role modeling, and mentoring adolescents and young adults to help them develop and sustain healthy, respectful relationship behaviors (32).

Our finding that many of these perpetrators were currently involved in a family legal court case at the time of the incident also highlights the importance of reducing fragmentation between the court/legal system and the mental health system. Recognition of the link among family court issues, mental distress, and homicide-suicide violence might help to improve communication between these two systems. Innovative approaches that might facilitate this communication without slowing the legal processes include using case managers to rapidly evaluate access to firearms, gather histories of domestic violence, and make referrals to mental health providers for those in need of counseling.

Furthermore, the fact that some perpetrators had previously been issued restraining orders highlights the need for effective interventions, once the violence has occurred. For example, a number of integrated domestic violence courts have been specifically designed to improve defendant accountability and to enhance victim safety (33). By working with a wide spectrum of stakeholders (e.g., civil attorneys and law enforcement, probation, and parole professionals), judges in these courts gain greater access to much needed information. These courts also increase coordination among criminal justice and community-based social service agencies to provide rapid and comprehensive victim advocacy and links to appropriate services (34).

In contrast to intimate partner-related homicide-suicide perpetrators, a high proportion of filicide-suicide perpetrators were found by this study to be in mental health treatment at the time of the incident. This finding may be expected because approximately half of these incidents are committed by females (35, 36), and females are more likely than males to seek care for mental health conditions (37, 38). This study also found that many of the filicide-suicide perpetrators who sought mental health treatment committed the violent act with a firearm. Feeling distressed, sad, or depressed and having access to a weapon of lethal means are associated with increased risk of lethal violence (39). The fact that many filicide-suicide perpetrators sought treatment before the incident indicates the potential opportunity for mental health providers to play a role in reducing the risk of homicide-suicide incidents involving children. For example, for parents who seek treatment for mental health conditions, providers may be able to evaluate access to firearms in the household, to obtain additional help for caregiving responsibilities, and to recruit family members to help monitor the patient’s treatment and progress (3).

The results from this study are subject to at least 4 limitations. First, because this study used a 24-hour period to define homicide-suicide incidents, the number of homicide-suicide incidents may have been underestimated. Second, the information on mental health and substance abuse is not routinely reported by all investigators, and relevant data sources (e.g., medical records) are not required for the NVDRS; therefore, this study probably underestimated the prevalence of these factors. Furthermore, because such histories are typically provided by family members and friends, the accuracy of the information is often unknown (2). Third, little information is available on the homicide-only suspects, thereby limiting our ability to compare them with homicide-suicide perpetrators. Fourth, medical investigators and police officers may be more or less likely to seek specific information (e.g., history of depression), depending on whether the event is a homicide-suicide incident, a suicide-only incident, or a homicide-only incident. This could account for the low prevalence of these characteristics among homicide-suicide perpetrators found in this study. These characteristics were found to be prevalent among filicide-suicide perpetrators, suggesting that this bias is unlikely, although investigators might be more inclined to assess mental health factors among those who perpetrate violence on children.

This study improves our understanding of homicide-suicide incidents by using the multistate NVDRS. Continued data collection will allow for better descriptions of homicide-suicide perpetrators, which will further inform prevention and intervention efforts to address this important public health problem.

Acknowledgments

Author affiliations: Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, Georgia (J. Logan); and Etiology and Surveillance Branch, Division of Violence Prevention, National Center for Injury Prevention and Control, Centers for Disease Control and Prevention, Atlanta, Georgia (J. Logan, Holly A. Hill, Michele Lynberg Black, Alex E. Crosby, Debra L. Karch, Jamar D. Barnes, Keri M. Lubell).

The authors are grateful to Bernard Auchter of the National Institute of Justice for his contributions to this paper.

The findings and conclusions in this manuscript are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention/the Agency for Toxic Substances and Disease Registry.

Conflict of interest: none declared.

Appendix

Table 1.

Characteristics of Homicide-Suicides Committed by Males Having Intimate Partner Problems and Using a Firearm, National Violent Death Reporting System, 2003–2005.