The Metropolitan Police officer suspected of kidnapping and murdering Sarah Everard was taken to hospital for a head injury sustained while in custody.
Scotland Yard said the suspect, who is in his 40s, was treated, discharged and returned to the police station where he is being held.
He was found collapsed and unconscious in his cell on Thursday after suffering serious head wounds, according to the Sun.
The Met said: “The suspect was taken to a hospital for treatment to a head injury sustained while in custody.
“He has since been discharged and returned to custody. We are not prepared to discuss further.”
Met Commissioner Dame Cressida Dick said on Wednesday night that human remains – which have not yet been identified – had been found in an area of woodland in Ashford, in Kent, by detectives investigating Sarah’s disappearance.
Sarah has lived in London for 12 years, but is originally from York and a former pupil of Fulford School.
The officer, who is in the Parliamentary and Diplomatic Protection Command, was held on Tuesday night on suspicion of kidnap before being further arrested on suspicion of murder and a separate allegation of indecent exposure the following day.
On the day of Sarah’s disappearance, he was reportedly working a 2pm to 8pm relief shift at the US Embassy in Nine Elms, south-west London, around three miles from where she was last seen.
According to unconfirmed reports, detectives are investigating whether he might have used his warrant card to entice Ms Everard towards his car before snatching her.
A woman in her 30s has been arrested on suspicion of assisting an offender.
Officers removed vehicles from outside a house being searched in Deal, Kent, where the officer is believed to have lived with his wife and two children.
Prime Minister Boris Johnson said he was “shocked and deeply saddened”, adding: “We must work fast to find all the answers to this horrifying crime.”
The events have prompted an outpouring of shock and anger as women across the country shared their own experiences of feeling unsafe.