Four men have been arrested on suspicion of causing death by dangerous driving after a woman was killed in a crash which also seriously injured two children, police said.
The fatal crash happened when the Vauxhall Astra in which she was travelling was in a collision with a black Seat Leon in Halifax, West Yorkshire.
It happened as the Astra was travelling from Chester Road, crossing the A647 Boothtown Road to go onto Woodlands Road, West Yorkshire Police said.
A spokesman said: "The front seat passenger of the Astra, a 25-year-old woman from Halifax, was pronounced dead at the scene.
"The male driver, aged 26, and two passengers - a girl aged seven and a boy aged four - were taken to local hospitals and are said to be seriously injured."
According to one report, the dead woman was the mother of the injured children.
Men aged 19, 20, 21 and 27 from Bradford were arrested on suspicion of causing death by dangerous driving, the spokesman said.
Officers also want to trace the driver of a blue X-registered Mercedes that was seen to be driving with the Seat Leon before the collision.
Anyone with information should call West Yorkshire Police on 101.