TRANSPORT police have re-launched an appeal to find a man who allegedly filmed himself performing a sex act on a train – and released pictures of other railway suspects.

He tried to film himself with a camera or mobile phone while performing a sex act on the 8.24am from London Marylebone to Bicester North as it left High Wycombe station on Friday, May 15, police said.

The train then passed through Saunderton, Princes Risborough, Haddenham and Thame Parkway, arriving at Bicester North around 9.40am, where it is thought the man left the train.

Station officials believe he went back to Bicester North the next day, Saturday, May 16, to ask about services to London.

He is described as white, about 30-years-old, with short, dark hair, of a muscular build and about 5ft10ins tall, wearing a suit and pilot style sunglasses.

It is thought he had some form of ID card around his neck which he then put in his breast pocket. Police released the first image, right, in a bid to find him last June and again today.

British Transport Police also want to talk to the man in the second picture in connection with an assault on train staff on June 25.

Officers want to speak to the main in the third picture over a cycle theft at Gerrards Cross station on March 5 last year.

The three pictured in the final image are sought over a moped theft at the station on September 2.

PC Dean Percival said: “Despite conducting extensive local enquiries into all of these crimes we are no further ahead in formally identifying those responsible.

“With the public’s help, and by working closely with Chiltern Railways, we want to ensure that people who commit such crimes are brought to justice.” Anyone with information can call BTP quoting Operation Jape - OP/93/10/11 - on 0800 40 50 40. Contact Crimestoppers anonymously on 0800 555 111.