Police Sergeant Matt Ratana died from a gunshot wound to his chest, an inquest into his death has heard.
Sgt Ratana was killed at a custody centre in Croydon as he prepared to search a handcuffed suspect, who is in a critical condition in hospital after he was also hit by a bullet.
He had been arrested for possessing ammunition and Class B drugs with intent to supply after a stop and search.
No police weapons were fired in the incident on Friday, which is not being treated as terror related.
On Thursday, a preliminary post-mortem examination report read out at Croydon Coroner’s Court said the chest wound caused his death.
Watch: Matt Ratana’s partner pays tribute
Detective Superintendent Nick Blackburn told the inquest the suspect, who was first detained in Pollards Hill, south London, was taken to a holding room with his handcuffs still on.
“The custody sergeant, Matt Ratana, entered the holding room,” DI Blackburn said.
“The suspect discharged the weapon several times, during which the sergeant and the suspect were injured.”
A revolver was recovered from the scene later.
Sgt Ratana was taken to St George’s Hospital in Tooting but pronounced dead at 4.20am, the inquest was told.
Senior coroner for south London, Sarah Ormond-Walshe, adjourned the hearing until a later date.
MPs, Prince Charles, celebrities, his partner and his Metropolitan Police colleagues have all paid tribute to the officer, who was nicknamed Matiu and was born in New Zealand.
In a statement on Thursday, the New Zealand high commissioner Bede Corry said: “As someone who was a police officer in New Zealand and the United Kingdom, he uniquely served both countries. We know he will be deeply missed.”