KITCHENER -- A fatal car explosion outside of the downtown Kitchener courthouse once thought to be caused by an improvised explosive device is now thought to have been caused by an incendiary device, police say.

The car exploded on Friday morning on Duke Street West near Frederick Street.

Initial findings had suggested that an IED may have caused the explosion, police said at the time.

"Further investigation revealed that an incendiary device was ignited within the vehicle, which caused the explosion," a news release issued Monday reads in part.

"The fire is believed to have been intentionally set and no suspects are being sought."

The Kitchener Fire Department, the Office of the Fire Marshal, the Office of the Chief Coroner for Ontario and the Peel Regional Police all assisted in the investigation.

"Investigators are no longer treating this as a criminal investigation," WRPS public information officer Ashley Dietrich said. "We believe the fire was intentionally set and are no longer looking for further suspects."

Police officials said over the weekend that they were waiting on an autopsy to help them determine the identity of the deceased.

"The identity of the victim is still unknown," Dietrich said. "We are still waiting for post-mortem results to come in."

It's not clear what sort of incendiary device was used or what motive the person may have had.