Four addresses are being searched by detectives investigating the fatal shooting of a police officer in a custody suite in London.
Metropolitan Police sergeant Matiu Ratana, 54, who was known as Matt, was shot in the early hours of Friday when a handcuffed gunman opened fire before turning the weapon on himself.
Deputy Assistant Commissioner Stuart Cundy said a 23-year-old man arrested on suspicion of murder following the incident at Croydon Custody Centre remains in a critical condition in hospital.
"Due to his state, we are not yet able to speak to him," he said during a news briefing at Scotland Yard.
He said the gun used had been recovered from the custody suite."We also have the CCTV from that custody suite, which shows the events," he said.
"And we have body-worn video of our police officers who were involved in the circumstances surrounding the arrest of the suspect.
"Our special investigators are carefully reviewing all of that footage, which will be considered alongside the accounts of the officers."
The four locations being searched are:
The custody centre where the shooting occurred
An area of London Road in Pollards Hill, south London, where the suspect was initially arrested
An address in Southbrook Road, Norbury
An address in Park Road, Banstead, Surrey
Enquiries at these locations include "rigorous forensic searches which are expected to take days to complete", police have said.
Sky News reporter Sadiya Chowdhury was told by a neighbour of the property raided in Norbury that police conducted a raid on Saturday morning and that they had been "coming and going all day".
The family had lived in the house "for a long time", the neighbour said, adding that the family was "alright" and had never been in trouble.
In Banstead, a neighbour said police raided a house in the early hours of Saturday morning, and some residents nearby reported hearing a loud bang.
One person said it sounded like a gunshot but others thought it was a bomb or explosion.
The property had been empty for "some time", according to another neighbour.
Sgt Ratana, who died in hospital, has been described as "big in stature, big in heart, friendly, capable, a lovely man and highly respected by his colleagues".
Friends say he was looking forward to imminent retirement, which he would have become eligible for in two months.
No police firearms were fired and the case is not being treated as terror-related.
A murder inquiry was launched by the Metropolitan Police, and the Independent Office for Police Conduct watchdog also began an investigation.
Prior to the shooting, the suspect had been arrested by regular officers following a stop and search, then handcuffed behind his back before being taken to the station in a police vehicle.
Sgt Ratana leaves behind a partner and adult son.