A man is recovering in hospital after being pushed in front of a Tube train as it approached a platform. It happened at Finsbury Park Station in north London.
Osei Kwaku, 30, suffered electrical burns.
British Transport Police (BTP) say they are treating the incident, which was witnessed by several people, as attempted murder.
Mr Kwaku, who was with a friend on the southbound Victoria line platform, escaped being crushed by lying in the well between the tracks, allowing the train to go over him.
A British Transport Police spokesman said: "We know the platform was quite crowded so there must be several people who saw something of what happened.
"We are looking at the CCTV evidence at the moment but it is really important that we hear from people who were there as soon as possible."
When the train had passed the victim climbed back onto the platform.
He is recovering in hospital after being treated for burns to his right leg.
Underground staff and the victim's friend chased the attacker but they were unable to catch him.
The incident happened 0935 GMT on Sunday.
Police want to speak to a man they describe as black and in his 20s, wearing a long dark coat.
They are appealing for witnesses to contact them on 020 7391 5275.
