Police in Fredericton continue to investigate the case of Peter Bryden, who was found unresponsive and seriously injured in the city early Saturday morning.

Officers were called to the area of Douglas Avenue and Main Street around 4:30 a.m.

Police say the 46-year-old man had attended the Harvest Jazz and Blues Festival Friday evening.

Investigators say Bryden sustained serious injuries and remains in critical condition at the Saint John Regional Hospital.

The cause of his injuries has yet to be determined and police aren’t ruling anything out at this time.

They say they are investigating all possibilities, including that Bryden may have been in an accident or may have been assaulted.

“We’re exploring all possibilities right now, all avenues, so it’s very possible that this could have been a motor vehicle accident or an assault or, in fact, an accidental fall,” says Staff Sgt. Matt Myers.

Preliminary investigation has revealed there were two or three individuals in the area where Bryden was located and police say they are “persons of interest” in the case.

“They were in the vicinity of where Mr. Bryden was found at 4:30 in the morning, so if anybody knows who those individuals are, or if those individuals themselves would come forward, that would certainly be of value to the investigators,” says Myers.

Investigators are also looking to speak with anyone who came into contact with Bryden Friday evening or Saturday morning.

Meanwhile, Bryden’s colleagues are expressing shock over the incident.

“He’s a regular guy, family man, great employee,” says David Innis, who works with Bryden at the Fredericton International Airport and has known him for many years.

“One doesn’t expect this to come out of the blue on a normal, every day that someone takes a wrong turn and is met with this kind of a violent event.”

Those who live in the area where Bryden was found say the area has changed over the years.

“It’s just a different crowd than when I was growing up,” says resident Katherine Holroyde. “It was more families and now all of them are rental units, instead of people that own their home anymore.”

Police want to hear from anyone who knows or saw anything related to the case, saying even minor details could help in their investigation.

With files from CTV Atlantic's Andy Campbell