Toronto Police are looking for witnesses to help them piece together the chain of events in a "grotesquely personal" murder and apparent suicide attempt involving a Via train Friday in Scarborough.

Police say a Scarborough man brutally attacked his ex-girlfriend and left her dead on the kitchen floor of her Danzig Street home Friday afternoon around 4 p.m., before throwing himself in front of a train about half an hour later. The suspect survived the collision with the train but lost his legs and is now in hospital.

"It was despicable and incredibly cowardly," Det.-Sgt. Stephen Ryan told reporters at a news conference on Sunday. He described the injuries to the victim as "grotesquely personal."

Lascelles Allen, 51, has been charged with first-degree murder and failing to comply with bail conditions that prohibited him from contacting the victim, 31-year-old Suraiya Gangaram.

Gangaram's 14-year-old daughter returned home from school at about 4:40 p.m. on Friday to discover her mother's body in the kitchen, Ryan said.

Police are now trying to account for the suspect's whereabouts in the 30 minutes between the time of the alleged murder and the moment when he was struck by the train, near Markham Road and Eglinton Avenue East. The tracks are about an eight-minute drive away from the scene of the homicide.

"We're trying to learn how he got from the homicide scene to the train tracks," Ryan said.

Allen and Gangagram had been in an on-again, off-again relationship that ended in 2014 when Lascelles was arrested for domestic assault, Ryan said.

"They lived together in the past," he told reporters.

Ryan said the meeting between the suspect and victim was pre-arranged. "There was some property of hers that he wanted and she agreed to meet him to return it."

Gangaram was the mother of three children between the ages of eight and 14. Lascelles was not the father of any of them.