A Winston Hills man found a horse’s head on top of his vehicle in Naomi Street on Thursday morning.
The man told police he was woken by loud banging noises at about 2.30am.
He went outside to find his car damaged and the severed horse’s head on its bonnet.
Police searched the area and found a trail of blood leading from the driveway.
They believe the horse’s head may have been taken from an abattoir. Forensic investigators have also examined the scene.
Anyone with any information is urged to contact Parramatta police on 9633 0799 or Crime Stoppers on 1800 333 000 or www1.police.nsw.gov.au/.