Metropolitan Police Sergeant Matt Ratana died from a gunshot wound to the chest after being fired upon inside a police station, according to a post-mortem report read at his inquest today.
The 54-year-old was shot as he was preparing to search a handcuffed suspect who had managed to smuggle a revolver into the custody suite in Croydon, south London on September 25.
Police are yet to speak to the alleged gunman, widely named as Louis De Zoysa, 23, who is in a critical condition in hospital after he shot himself as he opened fire. He was not named at the inquest hearing.
Sergeant Matt Ratana was shot dead in a London police station by a handcuffed suspect
Detective Superintendent Nick Blackburn said the weapon was discharged 'several times'.
A revolver was later recovered from the scene.
He told the inquest the suspect was first detained by police in Pollards Hill in south London at 1.30am.
The suspect was handcuffed and taken into custody on suspicion of the possession of ammunition and a class B drug.
He said: 'Upon arrival (at Croydon custody centre), he (the suspect) was taken to a holding room where he remained in handcuffs.
'The custody sergeant, Matt Ratana, entered the holding room.
'The suspect discharged the weapon several times, during which the sergeant and the suspect were injured.'
The inquest heard Mr Ratana was taken to St George's Hospital in Tooting but he was pronounced dead at 4.20am.
Mr Blackman said the preliminary cause of death given following the post-mortem examination was a gunshot wound to the chest.
No members of Mr Ratana's family, including his partner Su Bushby, were present for the hearing, although Mr Ratana's son in Australia was among those listening in remotely.
Sarah Ormond-Walshe, senior coroner for south London, adjourned the hearing until a further date.
Sgt. Ratana receiving a long and good service medal from the Commissioner Cressida Dick on May 31 2017
The Metropolitan Police officer of almost 30 years has been described as someone who epitomised the role police play in protecting others and, as head coach at East Grinstead Rugby Club, was said to be an 'irreplaceable figure'.
Sue Bushby, Mr Ratana's partner, paid tribute to her 'friend, confidant, support and soul mate' in a statement released last month.
She said: 'There aren't really any words for how I am feeling right now about the loss of Matt; about losing someone I loved, and was so close to, in such a tragic manner.
'I know Matt touched many, many people's lives with his friendliness, patience, kindness, enthusiasm and caring ways.
'I had the pleasure of sharing five years of my life with this lovely man - my gentle giant, with his infectious smile and big heart. I think of him with tenderness and love.'
Dame Cressida, Home Secretary Priti Patel and London Mayor Sadiq Khan attend the National Police Memorial in London shortly after Ratana's death