Toronto police are releasing images that show "portions" of the fatal shooting that claimed a young man's life last week.

On Monday, police announced that they are releasing images captured by security cameras. They're hoping to identify a person of interest who was seen inside a Bleecker Street seniors' apartment building on the evening Nisan Nirmalendran was shot dead, as well as the suspect and a suspect vehicle.

"The person of interest has not yet been identified, nor has the suspect," Det.-Sgt. Terry Browne told reporters during a news conference on Monday afternoon.

Nirmalendran was chased inside the vestibule of a seniors' apartment located at 55 Bleecker St., just north of Carlton Street on Thursday evening. Police were called to the scene just before 11:30 p.m., after gunshots were reported.

The 21-year-old Nirmalendran was found suffering from life-threatening injuries. He was rushed to hospital where he was pronounced dead.

Last week, police said they believe the person who killed Nirmalendran chased him into the vestibule of the Bleecker Street building — and that a female resident was used as a "shield" inside that space.

Browne said the person of interest came into the building several times that evening — including moments before the shooting occurred — and made attempts to disguise his identity. Security camera images captured on each of these occasions have been posted online by police.

The person of interest had "distinctive clothing," Browne said, including what appears to be a black-and-white scarf or shirt.

Police are also releasing images that show "portions of the interaction between the shooter and the victim," which include a sequence in which glass in the vestibule is blown out by gunfire.

While Browne said although police typically prefer not to release these types of images, he believes it is justified in this case given "the absolute disregard of the safety of innocent bystanders" by the person who shot Nirmalendran and the need to identify that shooter.

Police are also releasing videos of a pair of vehicles that were seen driving north on Sherbourne Street at the time of the incident.

"Witnesses report seeing three to four people fleeing from the area of 55 Bleecker St., and entering a silver van and dark-coloured compact car," Browne said.

Investigators want to speak to anyone who saw these vehicles on the night Nirmalendran was killed.

The victim is the brother of a man who was fatally wounded in a shooting that occurred in the basement of the Eaton Centre last year.

Nixon Nirmalendran died in hospital days after he was shot in the food court of the shopping mall.

Last Friday, Browne said there was "nothing to suggest that the two instances are related at all."