Detectives are appealing to anyone who has any information to make contact.
The man was attacked and as he caught a bus in Loughborough.
A number of people are believed to have tried to help the victim following the incident which happened in The Rushes at around 12.10am last Thursday (1 August).
Detectives are appealing to them and anyone else who has any information to make contact.
The victim, who is in his 20s, had got onto the bus when he was pushed off the vehicle by another man and dragged to the floor. The victim was kicked and his wallet, which contained cash, was stolen.
The victim shouted for help and a number of people came to his assistance. He suffered from a minor injury and did not require hospital treatment.
The male suspect is described as white, around 5ft 8 inches tall, and of medium build. He was wearing a grey tracksuit which had a black strip running down the side of the tracksuit bottoms.
Enquiries remain ongoing into the incident.
Detective Constable Alex Paterson said: “We understand a number of people were in the area at the time and were alerted to the incident when the victim shouted for help.
“Please think back to if you were in the area during the early hours of last Thursday. Did you see anything or do you recognise the description of the suspect? Did you try and help the victim? Do you have any other information which could help our enquiries?
“If you have any CCTV or dashcam footage, please also check this to see if you can help.”
Anyone with any information should call 101 quoting incident 19000403372.