Police in Lambeth are releasing three CCTV images of people that they would like to identify in connection with an assault on an off-duty police officer in Vauxhall last month.The incident happened at approximately 10:50hrs on Thursday, 17 July, near to Vauxhall railway station. The victim – a 57-year-old off-duty police officer – had just got off a train at Vauxhall station, when he noticed four people had exited through the barriers without using a ticket or Oyster card.He followed the group and noticed them approach bicycles that were chained to a bike rack nearby. One of the suspects then produced a pair of bolt croppers – at which point the victim phoned 999 and identified himself as a police officer to the group.One of the suspects then hit the victim over the head with the bolt croppers, causing him to fall to the ground before all four suspects ran off towards South Lambeth Road.The victim was taken to hospital for his head injury, but was discharged later that day.A 15-year-old boy was arrested in connection with the investigation on Wednesday, 23 July and has been bailed to return to a south London police in late September pending further enquiries.Detective Constable Sarah Francis, from Lambeth CID, who is investigating the incident, said: “If you recognise any of these people, or indeed witnessed this incident then please get in touch.“This attack happened in broad daylight and resulted in the victim receiving hospital treatment. I urge members of the community to come forward if they have any information with regards to the incident to help us catch those responsible.”Anyone with information about this incident should contact DC Sarah Francis from Lambeth CID on 020 8649 2191, or alternatively contact Crimestoppers anonymously on 0800 555 111, quoting the relevant image reference number.