A Milton Keynes man has been arrested following the death of a seven-year-old boy on Friday.
The child died on the A4146 Stoke Hammond bypass near the junction with the B4032 Leighton Road when a silver Toyota RAV 4 was involved in a collision with a blue DAF lorry at around 2.15pm.
The boy, who was a passenger in the car, died at the scene. Three people were taken to the John Radcliffe Hospital in Oxford where they were treated for serious injuries.
The 33-year-old man was arrested on suspicion of causing death by dangerous driving and has been released on bail while the investigation continues.
PC Sandra Terry from Bicester Serious Collision Investigation Unit said: “This is a very sad case where a young boy has lost his life.
“We are in the process of investigating the circumstances which led to these tragic consequences and so would urge anyone who was in the area before this time and saw the incident itself or who had seen either vehicle prior to the collision to please contact us as a matter of urgency.”
If you have any information please contact PC Terry via the Thames Valley Police Enquiry Centre on 101.