Toronto homicide detectives are investigating a double shooting that left two teenagers dead early Saturday morning.

Sealand White, 15, and Jermaine Derby, 19, were fatally shot around 2 a.m. when they were leaving a party at an apartment building at 605 Whiteside Pl., near Dundas Street East and River Street in the city's Regent Park neighbourhood.

The two were heading down the elevator to the main floor. The elevator opened on the main floor and both victims were shot.

One of the victims made his way through the front entrance of the apartment building to the front driveway where he collapsed, while the other victim remained on the elevator and went to an upper floor where he exited and collapsed.

One victim was pronounced dead at the scene. The second victim was taken to hospital where he succumbed to his injuries.

Det. Doug Dunstan said he's spoken with some of the people who were at the party but not all of them.

"We'd like them to come forward and talk to us and at least tell us what they know, whether they think it is important or not," Dunstan said. "It could be very important to us.

"Any time we can get a little bit of information from 50 different people, we could end up with a big story."

No suspects are in custody.

Anyone with information about the shootings is asked to call police or Crime Stoppers.