Toronto police have a suspect in custody after a man in his 50s was fatally stabbed on Tuesday night.

The victim, who has not been identified, was assaulted at an apartment building at 100 High Park Ave., near Bloor and Keele Streets, at approximately 8:40 p.m.

The assault occurred on the 6th floor of the building, police said Tuesday, but they have not said whether the victim or suspect lived on the floor.

He was transported to hospital in critical condition where he succumbed to his injuries.

Shortly after the stabbing, police arrested a man in his 20s, who was found naked and "acting suspiciously," police told CTV Toronto.

The suspect is facing second-degree murder charges. Police said Wednesday that they are not looking for other suspects.