A man was sexually assaulted by another male on board a London-bound train, detectives said.
The victim had been on the South Western Railway service from Staines to Clapham Junction on New Year’s Eve.
British Transport Police said as he walked down the carriage’s aisle a suspect, who was seated, groped him.
On Wednesday, the force released a CCTV image of a male wearing a black baseball cap and jacket. He appears to be smiling.
They added it was in connection to the incident which occurred at around 7.45pm on December 31.
A spokesman said: “Officers would like to speak to the man pictured, as they believe he may have information that could help their investigation.”
Anyone who recognises him is asked to contact BTP by texting 61016 or calling 0800 40 50 40, quoting reference 266 of 1 January.
Alternatively, they can also contact Crimestoppers anonymously on 0800 555 111.
