A cyclist has died following a road collision in Buckinghamshire near the Oxfordshire boundary.
Emergency services attended the scene on Aston Abbotts Road, which runs between Weedon and Aston Abbotts, after reports of a crash involving a rider and a red Seat vehicle.
The car driver remained at the location and is assisting detectives with their enquiries.
The male cyclist, aged 55, was declared deceased at the scene.
His family have been informed and are receiving support from trained family liaison officers.
A second car, a black Ford Puma, was also involved in the incident.
Its driver, a local man aged 40, was taken into custody on suspicion of a road traffic offence relating to the fatality.
He has since been released on police bail while inquiries continue.
Thames Valley Police is urging members of the public who may have witnessed the collision or the events leading up to it to make contact with investigators.
Detectives particularly want to speak to the driver of another dark-coloured vehicle who may have been travelling along Aston Abbotts Road in the direction of Weedon before the crash occurred.
Detective Sergeant Oliver Cahill-Smith, who is leading the investigation from the Serious Collision Investigation Unit, stated that officers are working to determine the precise circumstances of the incident.
Anyone who was driving through the area at around 8.10am on Tuesday morning and possesses dash-cam recordings has been asked to share that footage with police.
Those with information can quote reference 43260521732 when contacting the force.
Anonymous reports can also be submitted through separate channels for those who prefer not to be identified.