A man captured on security camera in an underground parking garage is now a suspect in the slaying of a millionaire Toronto philanthropist.

Until Tuesday, police had considered the young man seen entering and exiting the garage a "person of interest" in the shooting death of 66-year-old Glen Davis.

Homicide Det. Wayne Fowler says the suspect entered the parking garage after Davis arrived to have lunch with an acquaintance at a restaurant inside the building located on Eglinton Avenue, east of Mount Pleasant Road.

"It was unusual (the suspect) walked in using the on-ramp," Fowler told reporters at a press conference.

The man was in the garage for about half an hour before he was seen walking away.

Fowler said the parking area was used by an exclusive group of attendants, visitors and restaurant patrons. No one has recognized the suspect from images released by police.

"He didn't fit down there. He seemed out of place," Fowler said.

The suspect wore a bulky coat and backpack "for a purpose," such as to conceal a firearm, Fowler said.

Davis died from gunshot wounds while he was returning to his car on Friday afternoon.

Police said Davis was targeted for the grisly crime, but a motive is not yet clear.

Davis attended the restaurant on occasion, be he didn't arrive on a set schedule or at a set time, Fowler said.

Investigators have collected forensic evidence from the "extensive" crime scene.

While Fowler wouldn't say if there were signs of a struggle, he noted the suspect arrived wearing a hat but left the lot without one.

Davis, described as shy and quiet by friends, donated millions of dollars for various wildlife causes.

Investigators are also trying to determine if a baseball bat beating he sustained in December 2005 is somehow linked to his murder.