One man has been arrested in connection with a double murder in the city's east end.

Toronto police have arrested a suspect and charged him with the murder of one of two men found dead inside an apartment building on Danforth Road near Eglinton Avenue Friday.

They are still trying to determine what lead to the shooting before they lay any more charges, Det. Sgt. Savas Kyriacou told reporters at a news conference Monday.

Tyler Roulston, 18, and Adrian McFarlane, 19, were found on the 14th and 16th floors of the apartment building. Police say Roulston tried to flee the scene inside a 14th floor apartment but ended up collapsing from his injuries on the 16th floor.

Two people rushed to his aid and gave him CPR but Roulston succumbed to his injuries.

A third man was also found on the 14th floor suffering from several gun shot wounds but he is expected to survive.

"Another person that I'm not prepared to identify is still recuperating from injuries in hospital," Kyriacou said. "His medical prognosis appears to be positive. His injuries are no longer life threatening."

Kyriacou said detectives believe five people were involved in the shooting and that they are still looking for one person seen leaving the scene limping.

He said he's not sure what role the missing person played in the shooting.

"At this point we're trying to determine the sequence of events," he said. "It's a complicated investigation, a complicated scene. Until we have all the information in our hands, and determine the roles of everyone involved, we can't say that with certainty."

Kyriacou also said he wouldn't speculate on the motive.

Police have charged the owner of the 14th floor apartment, 19-year-old Mikhail Myrie, with the second-degree murder of McFarlane.