Cape Breton Regional Police are investigating a fire that claimed the life of a man at an apartment complex in Sydney.

Police and fire crews responded to the structure fire at 177 Mt. Pleasant Street around 5 p.m. Wednesday.

Neighbours say they spotted smoking coming from one of the units, and they watched as firefighters quickly knocked down the blaze.

They were devastated when they learned the body of 68-year-old Donnie Worobel had been found inside.

“Sad, sad, day; everybody is hurting,” says Debbie Green, a friend of the victim. “Nobody likes to see this stuff.”

Family and friends say Worobel was a lifelong resident of Whitney Pier who lived alone and kept to himself, but was well-known and well-liked in the community.

Stephanie Worobel is still in disbelief after learning that her brother perished in a fire that ripped through his apartment.

“It’s a real shock. It’s heartbreaking,” she says. “It didn’t affect me as much when my sister and brothers passed away, but this is so tragic because it was a fire.”

Landlord Troy McCarthy has been renting out apartment units for 18 years. He says this is the first time he has had to deal with a fire at one of his buildings.

“I liked Donnie personally. He was so soft spoken,” says McCarthy. “I felt sorry for the man, actually. He was single. Always pleasant, never had a bad word to say.”

The building contains three units, but no other injuries were reported.

People living in the other two units have been displaced due to smoke damage. There is no timeline on when they will be able to return home.

“The fire was contained to the unit of origin,” says Cape Breton Regional Fire Deputy Chief Chris March. “One person, we believe, is out of town, and the other is being accommodated by the Red Cross.”

The cause of the fire is under investigation, but March says it doesn’t appear to be suspicious.

“It appears as though it may have been an accidental fire, but again, the final investigation will be done by the fire marshal’s office and the police department,” he says.

Investigators remained on scene all day Thursday. Officials say they won’t know the exact cause of the fire until Friday.

With files from CTV Atlantic's Kyle Moore