Toronto police and paramedics help two of the four victims of a shooting at a highrise apartment building. One person died and two of the wounded collapsed at a nearby strip plaza. (Tony Smyth/CBC)

Toronto police are seeking the public's help after a shooting left one man dead and three others wounded at a highrise building near Jane Street and Highway 401 late Thursday.

A lack of working security cameras at the apartment building is posing a challenge for the investigation.

Police said shots were fired around midnight in the 15th-floor stairwell at 30 Falstaff Ave., prompting residents to call 911.

A man was found leaning against a door in the hallway with multiple bullet wounds. He was sent to hospital but later died. On Friday afternoon, police identified the victim as 19-year-old Aeon Grant of Toronto.

Two other wounded men were found at a strip plaza on Jane Street, just north of the building, and a fourth victim managed to get to hospital on his own, said Insp. Howie Page. All were reported in serious condition Friday.

"Casings have been located by the officers … in a stairwell and the scene is being protected. We [also] have a Toronto police gun dog searching the area and searching along Jane Street," Page said.

Police said all the victims appear to be under 20 years old. One person was taken in for questioning.

Det. Chris Neal said most of the security cameras in the apartment building were not working at the time of the incident. However, police are looking into whether there is surveillance footage available from nearby stores and highrises, since similar incidents have often involved multiple scenes, he said.

Police did a door-to-door canvass for witnesses Friday morning and planned to try again Friday evening. They were asking the public for information, adding that without surveillance video, they need the public's help more than ever.

The neighbourhood is the same one where 11-year-old Ephraim Brown was killed two years ago when he was caught in the crossfire of a gang shooting. Bill Sunberg, who dedicated a new community centre a few blocks away to Brown's memory, said the latest shooting affects the image of the community.

"It adds to that whole negative pall that hangs over us."