Three teenage boys were killed when they were hit by a car while waiting near a bus stop in west London on Friday evening.
The three, who were all aged about 16, and were heading to a birthday party, died at the scene.
The crash happened just after 20:30 GMT on Shepiston Lane, Hayes, close to a petrol station.
A 28-year-old man, who was in an Audi involved in the crash, was arrested and taken to hospital for treatment.
The boys’ next of kin have been informed, the Met Police said.
Other teenagers who were standing with the boys were uninjured.
Friends who left flowers at the scene on Saturday said the teenagers were going to a 16th birthday party.
Staff at the nearby Esso garage said a group had been fighting at the entrance to the forecourt just before the smash.
It is believed the Audi mounted the pavement just outside the entrance and travelled a few yards down the road before hitting a lamp post.
Tony Kitchin, 44, who works as security guard at a haulage firm nearby, said: “This road is busy 24/7. It’s a speed trap.
“I’m really surprised we haven’t had more horrific accidents like this.
“No parent should have to deal with that. My heartfelt sympathies go out to the family and friends of the people who lost their lives last night.”
Det Sgt Jane Shaw, from the Met’s serious collision investigation unit, said: “There are horrific circumstances that have resulted in three young people losing their lives.”
She appealed for anyone who saw what happened to contact the police.