A 26-year-old driver has been arrested on suspicion of murder after he allegedly ran over a knife attacker who had stabbed a woman in the street.
A 41-year-old man was hit by a car on Chippenham Road in Maida Vale, west London, at about 9am on Monday, police said.
One witness said he was attacking a woman and the confrontation moved into the road, where they were both hit by a car.
Witnesses tried to intervene to save the 43-year-old woman but she was fatally injured by the attacker, police said.
According to detectives, the woman knew her attacker, who also died at the scene.
The Met Police said the driver of the car had been arrested but it was not aware of any links between him and the two people who died.
The force said it is not looking for anyone else in connection with the incident.
Firefighters managed to free the man from underneath the car, but despite the efforts of paramedics, both people were declared dead at the scene.
Witness Mulugeta Asseratte told PA news agency: “It is a very terrible incident. I was coming up from the bakery to Chippenham Road and suddenly heard shouts of ‘stop it, stop it’ and it was a girl being attacked by a gentleman.
“All of a sudden it moved to the street and no sooner than they reached the street than a driver came and hit both of them.
“We were all shocked and shouting and my heart goes out to the families of this fatal incident.
“This is something one sees in movies, not in real life.”
Detective Chief Inspector Jim Eastwood, of the Met’s Specialist Crime Command, added: “This was a terrible incident that occurred in broad daylight on a busy London street.
“It also appears that a number of members of the public bravely tried to intervene to stop the attack.”
The families of the man and woman who died have now been told.
Anyone who saw what happened or has relevant information is asked to contact police on 101 quoting the reference 1496/24jan, or to stay anonymous contact Crimestoppers on 0800 555111 or online.