A man has been arrested on suspicion of causing death by dangerous driving after a crash which killed two boys.
Sanjay Singh, 10, and Pawanveer Singh, 23 months, were in a BMW with their mother when it was in collision with an Audi S3 in Wolverhampton on Thursday.
A 23-year-old man from Birmingham was arrested on Sunday, police said.
A 31-year-old driver of a third car, a Bentley, who was arrested at the scene, has been released pending further investigation.
West Midlands Police said the car being driven by the boys' mother was turning right from Birmingham New Road into Lawnswood Avenue when it was struck at about 20:45 GMT.
Det Sgt Paul Hughes, of West Midlands Police, said: "We would appeal to the public to keep contacting us with any information.
"Pawanveer and Sanjay's family have been informed of this afternoon's development, and we continue to support them through this terrible period."