Detectives from British Transport Police’s sexual offences unit are looking to identify him following multiple exposures on the London Underground network.
On each occasion a man sits near to a woman on a Tube carriage and pretends to sleep. He then exposes and touches himself inappropriately, opening his eyes slightly to stare at the woman.
The first incident was reported to BTP last July on board a train between Green Park and Wembley Park. The second and third incident were reported on February 22 and 26 this year on board Metropolitan Line trains between West Harrow and Finchley Road and Baker Street and Croxley. The fourth incident happened on a train between Baker Street and Northwood Hills on 10 March.
The incidents occurred during the early evening between 4pm and 8pm.
Detectives would like to speak with the man in these CCTV images as he may have information which could help with the investigation.