The severed head of a pig was found this morning outside the entrance to the office of the federation that represents Montreal police officers.
Police investigators are hoping video surveillance will help them find out who put it there.
The macabre discovery was made by an employee who was arriving for work.
The head was placed on top of a pentagram that was scrawled on the ground.
Several wooden branches in the form of a human were also attached to the main doors.
Police say a note was left behind but they would not comment on its contents.