A woman was sexually assaulted as she slept on a train after enjoying a night out with friends in London.
The 25-year-old boarded the train at Charing Cross and sat in one of the last two carriages on Monday, April 28.
She quickly fell asleep and woke up sometime between 12.25-12.50am to find a man sexually assaulting her.
The victim managed to push the man away and fled the train when it arrived at West Wickham station a few moments later.
CCTV images of a man police believe hold vital information about the attack have been released.
DC Andy Parkinson, leading the investigation, said: “We believe the man pictured boarded the train at Lewisham station and got off at West Wickham. I am eager to speak to him as I think he might have vital information.
"If you recognise him or think you may have witnessed the incident, please get in touch. We take all reports of sexual assault extremely seriously and are doing all we can to catch the individual responsible.”
Call 0800 405 040 or 0800 555 111.