Authorities say they believe the deaths of a Monrovia mother and her baby fatally struck by a Metro train on Wednesday were the result of a murder-suicide.

The 36-year-old woman was carrying her 15-month-old son when she stepped in front of an L Line train, said Lt. Jaime Alfaro, who heads Monrovia’s police detective bureau.

He said she had a history of depression.

The collision happened near Duarte Road and California Avenue around 8:45 a.m.

The woman’s husband was at work when she walked from home to the train tracks, Alfaro said, bringing along her son.

The train engineer saw her walk into the train’s path but didn’t learn about the child, Alfaro said, until he was being checked out at a hospital.

“He was distraught,” the lieutenant said.

Public records show the woman was a nurse whose California license expired in 2018, after which she was raising her son. She had no record of discipline.

The Police Department, Alfaro said, can provide the public with phone numbers to programs for people needing help.