The suspect accused of fatally shooting a sergeant at Croydon Custody Centre is still yet to be questioned by detectives, the Met Police has said.
New Zealand-born Sgt Matiu Ratana died in hospital after being shot by handcuffed suspect Louis De Zoysa.
The 23-year-old remains critically ill at St George’s Hospital in Tooting.
Detailed searches are continuing at Mr De Zoysa’s family home in Norbury, south London, and at a farmland in Banstead, Surrey.
Officers are also searching a location in central London, and a man who was arrested in Norwich on Sunday on suspicion of supplying a firearm remains in custody at south London police station.
The search of the Banstead farmland, on Park Road, includes access to several derelict buildings and more than 30 acres of land and is expected “to take days to complete”.
Met Deputy Assistant Commissioner Stuart Cundy said “a number of witnesses” had been traced and provided “significant information” about events leading up to the shooting.
“It is five days since the murder of our colleague and our work continues at a high tempo,” he said.
“We continue to pursue multiple lines of enquiry and consider the results of initial forensic examinations, including of the gun recovered from custody.
“The murder of Sgt Ratana sent shockwaves through the Metropolitan Police Service. Nevertheless, his colleagues are determined to find justice for him and his family.”
The Met said specialist detectives continued to investigate the murder and not counter terrorism.
A JustGiving page has been set up in memory of Sgt Ratana, created by the Met Police Hayes Sports Club, known as The Warren, where the 54-year-old regularly visited.
The club is independent of the Met Police force, although the Met said it recognised this as an official fundraising account.
Funds will be distributed in Sgt Ratana’s memory, for his benefit, The Warren said.
The Independent Office for Police Conduct (IOPC) said Mr De Zoysa was arrested on suspicion of possession of Class B drugs with intent to supply and possession of ammunition.
The IOPC confirmed he was handcuffed with his hands behind his back and had been taken to the custody centre in a police vehicle, before being escorted into the building.