Detectives from Transit Crime Investigation Unit are appealing for information following an incident in Bundoora last week, Victoria Police say.
Investigators have been told a teenage girl was standing at a bus stop on Settlement Road about 1.55pm on Wednesday, 26 July when a man walked past her.
The man then walked back and forward past her several times before stopping close to the victim.
She saw he had exposed his genitals and then started to rub them.
The man did not say anything to the victim, however she screamed and left the area.
The man then ran down Settlement Road before heading along Brownhill Street.
Police patrolled the area afterwards but were unable to locate the man.
The man is described as being perceived to be of Caucasian appearance, aged between roughly 16 to 19-years-old, about 175cm tall with a thin build.
At the time he was wearing an orange fluro "tradie" style hooded jacket without logos, dark blue workpants and dark work boots.
His clothing was also described as being very clean.
Detectives from Transit CIU are investigating and are appealing for anyone who saw the man in the area at the time or has other information to come forward.
Anyone with information is urged to contact Crime Stoppers.
