Homicide investigators in Toronto say they suspect a 15-year-old teen was "targeted" by the person who shot and killed him in an apartment stairwell on Friday afternoon.

"This kind of a murder, I would suggest, is not a random murder," said Det. Justin Vander Heyden.

Tyson Bailey was found wounded and bleeding in the stairwell of an apartment building in the city's Regent Park neighbourhood. He had been shot at least four times and died a short time later at nearby St. Michael's Hospital.

"Tyson was either lured here, or came here for a reason," Vander Heyden said outside the crime scene at a Toronto Community Housing highrise at 605 Whiteside Place. "He didn't just wander into the 13th floor stairwell. So given those facts I would suggest it is a targeted shooting."

Investigators say the boy did not have a criminal record and they do not believe he was involved with gangs. The motive for the shooting remains a mystery, for now.

"By all accounts he was a fine, young man," said Vander Heyden.

"There is absolutely nothing in Tyson's background or in his current lifestyle that we can determine any kind of gang affiliations or any kind of gang association whatsoever."

Police say they are looking for two men who they describe as persons of interest.

One man is a white male, 25 to 30 years old. Vander Heyden described him as "tall and skinny, with a pockmarked or acne covered face."

The other person of interest is a black male, 25 to 30 years old, shorter than the other person, wearing a thick, black jacket.

The shooting happened just after 2 p.m. on Friday. Police received a number of calls and found the teen a short time later.

Police say Tyson did not live in the building and so far they have not been able to determine why he was there.

"Tyson lives in Toronto but does not reside at this address," Vander Heyden said. Police hope the public might be able to help explain "why Tyson was here this afternoon, which may lead to information about suspects and persons of interest."