Fawkner Sexual Offence and Child Abuse Investigation Team are investigating an incident in Pascoe Vale.
Investigators have been told a 39-year-old woman was riding her bike along the Moonee Ponds Trail about 4pm on October 13.
She stopped at Herbert Reserve to rest when a male approached, sat down and started to talk to her.
The victim stood up and attempted to leave and the male attempted to hug her, but she offered him a handshake.
He grabbed her hand and pulled her toward him and placed her in a headlock and threatened her if she screamed.
She managed to get back to her bike and ride home and was not physically injured.
The male was last seen walking on the creek path toward a construction area at the end of Main St.
The victim was not physically injured.
He is described as 175cm tall with a medium to large build and short cropped black hair with a white spot at the back behind his right ear.
He was wearing a khaki green t-shirt with a white graphic on front, black knee length shorts with white thread and sky-blue Nike running shoes with white soles.
Investigators have released a facial composite of a man they believe may be able to assist with their enquiries and an image of shoes similar to those he was wearing.
Anyone who witnessed the incident or with information is urged to contact Crime Stoppers on 1800 333 000 or www.crimestoppersvic.
com.au