Frankston Sexual Offences & Child Abuse Investigation Team detectives are investigating four separate sexual assault incidents, across the Mornington Peninsula, during January and February.
It is understood an unknown offender was riding his bike when he approached four women at separate locations and struck them on the backside.
The first incident occurred on The Boulevard in Somers on 22 January about 10.30am.
The second incident occurred on Tasman Road in Somers on 31 January about 6.10pm.
The third incident occurred on Peterson Street in Crib Point on 1 February about 5pm.
The fourth incident occurred on Sandy Point Road in Balnarring on 13 February about 5pm.
In each of the incidents the male approached the victim and struck them on the backside, before fleeing the scene on his bike.
Investigators have released images of a bicycle and a backpack associated with a male that may be able to assist them with their enquiries.
The boy is perceived to be Caucasian in appearance, about 14-19 years old with blue eyes and blonde or brown hair.
He was last seen wearing a light-coloured t-shirt, black pants, a navy-blue Nike backpack with a vertical white stripe on it and riding a white and blue bicycle.
Anyone who recognises the male, has dashcam or any information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report at www.crimestoppersvic.com.au.
