Two men have been killed by a Tube train after being caught spraying graffiti in east London.
British Transport Police said the pair - aged 19 and 21 - ran straight into the path of the oncoming District Line train in Barking after security staff called out to them.
A third person, aged 23, was arrested, while one other fled the scene.
The men are understood to have been struck by a westbound train heading towards Ealing Broadway at around 11pm on Friday night.
He added that another moving train, behind the tube that killed the pair, might also have been involved in the accident.
"The boys were graffitying the trains," a spokesman for British Transport Police, which is investigating, said.
"There were four boys altogether and they were noticed by security, who called out to them.
"Then they ran off and two ran right out in front of an oncoming train."
Police suspended services in both directions after the incident on the westbound track between Upney and Barking.
Forty-one passengers on one train had to be walked back along the track to Upney station where they finished their journey by taxi.
Services were up and running again by 8am, but there were still some delays on the line.