City police say the autopsy was delayed Thursday afternoon.
A woman found the head while walking in a northeast neighbourhood Wednesday morning.
Investigators are trying to determine whether it belongs to the body of a man found in a rural area east of the city on the weekend.
Local media say residents of Ranfurly have been talking about how the body was decapitated and found lying in a ditch next to a running pickup truck.
An autopsy was performed on that body Monday and the medical examiner ruled the death a homicide.