A woman was sexually assaulted in her South Fremantle home early this morning by a man armed with a knife.
Police say the woman about 1.45am to find the man in her bedroom.
The man was chased from area and may have fled partially clothed.
He is described as being aged 17 to 18, 165cm tall with a slim build. He was wearing a blue T shirt.
Police located a knife, possibly the one used by the offender, near the address and are urging all residents in the area to check their yards and bins for any unusual items such as clothing.Anyone who saw anything suspicious or has any information should call Crime Stoppers on 1800 333 000.