Toronto police believe a 72-year-old woman whose body was found in a burning apartment over the weekend was murdered, investigators said at a news conference Monday.

The woman’s name has not been publicly released as police are still trying to contact her next-of-kin.

Meanwhile, police are trying to locate an unidentified man seen on the same floor as the victim's unit. He was seen leaving the building shortly before police received a 911 call alerting them to the fire.

Police say it was the building superintendent who called the emergency line.

The woman was found Saturday afternoon inside a second-floor unit of a North York apartment building located on Yonge Street near Cummer Avenue. She was pronounced dead at the scene.

Fire officials found "multiple origins" of the blaze inside the apartment. Investigators also found signs of trauma on the woman's body, leading them to believe she was dead before the fire began.

"Everything leads toward foul play," Det.-Sgt Terry Browne said.

Nonetheless, Browne said investigators believe this was an isolated incident.

"There's no need for other residents of the building to concern themselves at this point," he said.

At the news conference, police said the woman did have a criminal record but it dates back to 2007 and 1997 and was related to the sex trade.

Investigators said they are not sure if the woman, who uses the aid of a walker, was still involved in the sex trade but that people were often seen visiting the apartment where she lived. Police also said they believe she had lived with her mother who had recently died.

Police were able to find video of the man in question on a surveillance camera installed in the area. They have released those images to the public and describe the man as being black and in his mid-twenties. He is about six-foot-one and was wearing a white T-shirt with plaid shorts, white running shoes and a mostly grey baseball cap.

Meanwhile, investigators are canvassing the area for evidence and witnesses.

Police are asking anyone with information to contact detectives at 416-808-7400. Anonymous tips can be left with Crime Stoppers at 416-222-TIPS (8477).