Investigators are trying to piece together exactly what happened late Sunday night when a routine traffic stop ended with a Toronto police officer stabbed in the neck and a male driver shot.

According to the province's Special Investigations Unit, the officer "stopped a motor vehicle for a traffic stop in the area of Northmount Avenue and Delhi Avenue," near Bathurst Street and Highway 401.

What happened after that is not clear. 

According to Toronto police Chief Bill Blair the officer was "alone at the time" of the incident.

Blair told CBC News the officer — Const. Jeff Blair, a 12-year veteran of the force with two children — suffered a "very serious injury which could've been a lot worse."

Blair, who is no relation to the police chief, underwent emergency surgery at Sunnybrook hospital and is reported to be in stable condition.

The chief said the wounded officer is "going to be OK" and released a YouTube video to update the public.

Toronto Mayor Rob Ford issued a statement Monday, saying that "it is important to remember the sacrifice Toronto's police officers provide to ensure our well-being."

The mayor wished the injured constable "a full and fast recovery."

The man who was shot also is undergoing treatment at Sunnybrook. 

Police will only say he is 38 years old and is in critical condition.

The SIU is now investigating. It has assigned six officers to the case.

For the wounded officer, the location of the incident was fortuitous — right outside the home of Mike Salb, a 22-year veteran of the Toronto Fire Department.

Salb, 52, was getting ready for bed when he heard a noise outside.

"There was a commotion outside the house. I heard the officer say, 'Stop. Police.' Five shots rang out. I went to the window to have a look out. I saw the officer raise his gun, fire two more times, and then I ran out."

Salb said he put on a jacket with Toronto Fire Department insignias on it "so that when police arrived they'd know I was

[with the fire department.]

"I told the officer I was a firefighter, he asked me to secure his gun, which I then took into my house, I grabbed a flashlight and some paper towels, I then came back out to render first aid to the officer," Salb told CBC News.

Within a few minutes Salb said, "police were coming from everywhere. They secured the victim and then the ambulance arrived and the officer was stabilized and then transported to hospital."

The man who was shot was "face down against the curb. He wasn't moving very much. He did move a little bit — but he wasn't threatening in any way," Salb recalled.

Asked how he felt after learning the wounded officer would be OK, Salb said he was "definitely elated that in some way I could help him out."