Toronto police have a mystery on their hands after a man was found lying face-down and fighting for his life on a Scarborough road Thursday.

"We are asking anyone who lives on that street to contact police if they have any security footage," Toronto police constable Clint Stibbe said.

Traffic Services is leading the investigation into how the 59-year-old man ended up seriously injured and without a pulse near Lawrence Avenue East and Rouge Hills Drive just after 11 p.m. Thursday night.

Investigators have been canvassing the area Thursday and hope speak with anyone who might have seen what happened to the man. He's now in hospital in life-threatening condition.

"[It] hasn't been determined yet whether he was struck by a vehicle, assaulted or by some other means received those injuries," Stibbe said.

Police say that the man's injuries are so serious that if he was struck by a driver who left the scene, there will likely damage to the vehicle, as well. In hit-and-run incidents some debris is usually left behind from the damaged car, they say. But as of now, there is no clear evidence of that nor any other answer to this mystery.

Residents in the neighbourhood told CBC News they know the injured man.

"[He's] excellent, got a beautiful heart," says Veronica Doobay."It's really sad because it's a friend of ours, right next door."

Police believe the victim was injured between 10:30 p.m. and 11 p.m. Thursday. But neighbours say they didn't notice anything suspicious.

"We had the dogs out about quarter to eleven last night but I didn't see anything," neighbour Bill King said.

"We've never had any problems around here. Very quiet. A lot of retired people here," Jean King said.