Police are searching for a man who dragged an 18-year-old woman into parkland in Craigieburn in broad daylight.
The Fawkner Sexual Offences and Child Abuse Investigation Team said the man grabbed the woman and dragged her into Malcolm Creek Park on Grand Boulevard about 5.40pm on Thursday.
The woman screamed, alerting a passer-by who intervened, causing the offender to flee.
The man is described as Caucasian, aged in his 20s and about 183 centimetres tall, with a thin build and dirty brown/blonde hair.
He was wearing a black baseball cap and a white T-shirt.
Anyone who witnessed the incident or saw suspicious behaviour in the area is being asked to contact Crime Stoppers on 1800 333 000.