Kent Police arrested a 37-year-old Tukwila man for investigation of murder in the April 22 vehicle-train collision as the man reportedly killed his female passenger by strangulation.

“As detectives concluded their investigation, they observed injuries to the deceased female that were suspicious and inconsistent with the hit-and-run collision,” according to Kent Police news release on Tuesday.

The King County Medical Examiner’s Office determined that strangulation was the cause of death.

A 36-year-old Seattle woman was found in the passenger seat with life-threatening injuries and died at the scene despite life-saving efforts by officers and paramedics. The man and woman had a past relationship and were familiar with each other, police said.

“It has now been confirmed that the female died of trauma not related to the collision and this has turned into a homicide investigation,” according to the release.

The man might have been under the influence of drugs or alcohol when he went through a signal and crashed into a freight train that was moving at slow speed at the crossing near South 212th Street and 77th Avenue South, according to police. A witness saw the vehicle leave the scene.

Kent Police arrested the man after the collision for state Department of Corrections violations, said Assistant Chief Jarod Kasner. The man remains in custody.

“There is a possibility of impairment, but we have not received lab results,” Kasner said. “Our investigation is ongoing.”

Detectives are processing evidence and following leads to establish the sequence of events that led to the killing.

After the collision with the train, officers spotted the vehicle nearby and performed a pursuit intervention technique (PIT maneuver) to stop the vehicle, Kasner said.