A police officer who remains in a life-threatening condition after being seriously injured in a crash while on duty has been named as PC Christopher Miller.
The Thames Valley Police officer was involved in a collision with a white BMW on the B416 Bells Hill in Stoke Poges, Buckinghamshire, on Thursday night.
The incident occurred around 10.20pm on May 22, and the BMW did not stop at the scene.
PC Miller, who serves with the Roads Policing Unit, sustained very serious injuries and remains in hospital in a critical condition.
PC Christopher Miller was hit by a car while on duty on Thursday
PA
Four people have now been arrested in connection with the collision.
Two men, aged 28 and 38, both from Slough, were arrested on suspicion of attempted murder and causing serious injury by dangerous driving. They remain in custody.
A third man, aged 43, also from Slough, was arrested on suspicion of assisting an offender and perverting the course of justice. He has since been released on police bail.
Thames Valley Police confirmed on Sunday they had arrested a fourth person, a 37-year-old woman from Slough, on suspicion of assisting an offender and perverting the course of justice.
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Deputy Chief Constable Ben Snuggs speaking at Taplow Roads Policing station, in Maidenhead, after Pc Christopher Miller was left fighting for his life in hospital after being seriously injured in a collision while on duty in Buckinghamshire on Thursday
PA
Speaking to reporters near the scene, Detective Superintendent Will Crowther said: "On Thursday, one of our officers was seriously injured whilst simply doing his job. He is currently in hospital with life-threatening injuries."
Det Supt Crowther confirmed the injured officer as PC Christopher Miller from the Roads Policing Unit.
He said: "Christopher has sustained very serious injuries and remains in hospital in a critical condition.
"His family are being supported by specially trained family liaison officers, as are his closest colleagues."
Thames Valley Police said on Sunday afternoon that PC Miller remained in a life-threatening condition in hospital.
Senior Investigating Officer Detective Chief Inspector Will Crowther speaking at Taplow Roads Policing station, in Maidenhead, after Pc Christopher Miller was left fighting for his life in hospital after being seriously injured in a collision while on duty in Buckinghamshire on Thursday
PA
Officers are continuing to appeal for witnesses to the incident and urge anyone who may have footage to come forward.
"We want to hear from anybody that witnessed a white BMW driving erratically in the areas of Stoke Poges and Slough between 8pm on Thursday evening until around 1am on the morning of Friday, May 23," Det Supt Crowther said.
"We believe that after the collision the BMW will have sustained damage to the front of the car."
Police are asking the public to check dash-cam, CCTV or doorbell footage which may have captured something that could assist with the investigation.
Anybody with any information is asked to contact Thames Valley Police, either online or by calling 101, quoting reference 43250252869.
Thames Valley Police Deputy Chief Constable Ben Snuggs said: "All officers should expect to return home safely after each tour of duty, and we wish Christopher a swift and full recovery."
He added: "We have all been affected by this, right across Thames Valley Police.
"I want to thank our local communities for all their support and the wider public for the supportive messages we have received."
Det Supt Crowther emphasised the determination to bring those responsible to justice, stating: "I believe there are people out there that know who is responsible.
"If you know what happened or have information that could help, I urge you to please come forward. You can do so in the strictest of confidence."
