Police are hunting an attacker who offered to help a man in a wheelchair - and then sexually assaulted him.
Police want to trace a man in a jumper with hoops on its sleeve
The 25-year-old victim had been out for a drink with friends in Lowestoft, Suffolk, when he was approached by a man who said he would push him to a pub.
However, the attacker guided the chair to a deserted shop loading bay and forced the man to commit indecent acts.
His ordeal continued as he was then shoved to a car park and an alleyway where further assaults took place after 2300 GMT.
The man then fled, and the distressed victim made his way into London Road North, where he met a group of youths who took him to the police station.
Officers discovered the 25-year-old had lost his blue Nokia 3330 mobile phone.
Suffolk Police are appealing for anyone who finds the phone to get in touch with them.
The man police are looking for in connection with the attack is described as white, 5ft 6ins tall and of thin build.
He had short blond hair and was wearing jeans and a distinctive white top with black hoops on each sleeve and black patches under the arms.
Detective Inspector Jim Keeble said: "This is a particularly nasty and vicious attack on a vulnerable victim."
Officers are examining CCTV pictures of the area in which the incident took place and are asking anyone who thinks them may have information about the offence to contact Lowestoft CID on 01986 835100.