Banyule Crime Investigation Unit detectives have arrested and charged three men following an alleged incident in Reservoir on 8 April.
Investigators were told a 17-year-old boy had boarded a replacement bus at Thomastown Railway Station about 7.45pm alongside three other males.
The trio allegedly assaulted the victim and stole his hat, headphones, phone, charger and scooter.
The victim exited the bus at Reservoir Railway Station and later reported the matter to police.
Later that day, police arrested a 19-year-old Mill Park man, 18-year-old South Morang man and 18-year-old Epping man.
All three have been charged with armed robbery, theft and assault-related offences.
The South Morang man was also charged with bail-related offences.
The men have been remanded to appear at Melbourne Magistrates’ Court on 4 July.
Police understand there were a number of people on the bus at the time who may have witnessed the alleged incident.
Anyone with information is urged to contact Crime Stoppers on 1800 000 333 or submit a confidential report online at www.crimestoppersvic.com.au