The boy appeared in youth court Thursday to face charges for attacking a person on the street.
Police then handed over the teen, who cannot be identified because of his age, to authorities in the Waterloo region.
He is considered a suspect in the stabbing death of a 22-year-old man in Cambridge, Ont.
Joseph Batten was killed early Dec. 17 during a fight outside a hip hop concert.
Three other people have already been arrested in connection with the killing.
The teen, who is originally from Hamilton, was visiting Montreal with his family when he was arrested.