Blair County President Judge Jolene Kopriva said a final rebuttal witness for the prosecution will take the stand this morning when court resumes a half-hour earlier than usual.

The jury will hear closing arguments after lunch.

That will be followed by her charge to the jury outlining each of the charges Horner is facing in the April 6, 2009, killing of two people, the wounding of a third and two robberies.

Horner, 31, formerly of Johnstown, is accused of shooting to death Scott Garlick, 19, an employee of the 58th Street Subway. Horner allegedly wounded another employee, Michele Petty, and robbed the store of $133 cash.

Police say he then went several blocks to where he shot and killed Raymond Williams, 64, a retired insurance executive who for many years had an office in Vinco. Williams and his wife, Tina, had relocated to Altoona about five months prior to the shooting.

Police say Horner took Williams’ car keys and mail.

Prior to the evening adjournment Monday, Horner was brought before the bench, sworn in and in a barely audible statement said he would not be taking the witness stand in his own defense.

Under questioning from Kopriva, Horner said the decision was entirely his own and that his thinking was not impaired by any type of drugs.

It was prescription drugs that dominated the testimony Monday, with dueling experts offering widely varying opinions on what role Horner’s prescription drug use may have played in his alleged crimes.

While Horner admits pulling the trigger, his defense attorney, Thomas Dickey, maintains he lacked the mental faculties to form specific intent needed for a first-degree murder conviction because of the prescription drugs.

If Horner is convicted of first-degree murder, he will face the death penalty.

Horner, who served two tours in Iraq and one in Kuwait prior to his discharge from the Army for medical reasons, suffers from post-traumatic stress disorder, something which for several months was believed would be the basis for his defense.

But experts for the defense and the prosecution said Monday that Horner’s PTSD did not play a role in his actions, which included shooting out the utilities at the rear of the Subway prior to opening fire on Garlick and Petty.

That is where any agreement between the experts ended.

Dr. Ernest Boswell, a clinical psychologist from St. Paul, Minn., who has an extensive background working with Iraq war veterans, said he has assessed 3,000 to 4,000 soldiers for the military, and Horner’s actions don’t fit the pattern.

However, the PTSD resulted in medications that created other problems, he said.

“I think there’s a significant amount of credible information to say he has PTSD,” Boswell said. “I do not believe the PTSD in and of itself is a causal pathway to this. It was not a flashback consistent with PTSD.”

Rather, Boswell said, Horner’s actions point to disorientation and confusion, the result of a drug- induced delirium that can be brought on by use of benzodiazepine, a psychoactive drug sometimes called Clonazepam. It was one of a number of prescription drugs found in Horner’s home the night of the incident.

“During the whole incident, his pattern of behavior is illogical, it’s irrational, it’s not put together,” Boswell said.

When asked to explain why Horner appeared normal earlier in the day when he spent several hours at the Holiday Bowl and why he ran from police to avoid capture following the shootings, Boswell said the disorientation “waxes and wains,” an assertion rejected by an expert for the prosecution.

Speculation is that Horner’s use of the drug may have been greater than prescribed on the day of the incident.

Dr. Robert Middleberg, a forensic toxicologist from Willow Grove, said the drug is heavily used nationwide – as many as 23 million prescriptions in 2010 – with relatively few problems.

It acts to depress the central nervous system and users become lethargic and tired. Conditions are similar to those caused by drinking alcohol, Middleberg said.

In viewing a video of Horner at the bowling alley prior to the shootings and hearing of his later actions, Middleberg said he saw nothing that would suggest drug-induced delirium.

Dr. Steven Samuel, a forensic psychologist from Philadelphia, testified for the prosecution that an extensive review of Horner’s records and a 45-minute interview with him at SCI-Cresson led him to believe Horner does have PTSD, along with attention deficit disorder and other mental problems.

“He certainly has a myriad of problems, but I don’t think they have any direct impact on what happened here,” he said.