A man is facing a life sentence after being found guilty of murdering Met Police sergeant Matt Ratana in a police cell shooting.
Louis de Zoysa fired an antique Colt revolver at Sgt Ratana at Windmill Custody Centre in Croydon, South London, on September 25 2020, after smuggling it in beneath his coat.
New Zealand national Sgt Ratana, 54, had been weeks from retirement when he was shot in the chest and killed.
De Zoysa, who was in handcuffs at the time, had been arrested earlier that evening for possessing cannabis and ammunition, although had not told officers he had a gun.
Horrifying CCTV footage which was shown to the jury depicts de Zoysa suddenly producing the gun and firing a shot before officers wrestled him to the ground.
Sgt Ratana died from his injuries, becoming the first British officer killed inside a police station.
Another shot hit de Zoysa in the neck, later causing a stroke which has left him with severe brain injury and in a wheelchair.
The 25-year-old from Banstead, Surrey, a former UCL student who works as a coder for HMRC, stood trial at Northampton Crown court for Sgt Ratana's murder, with a jury today finding him guilty.
De Zoysa gave some of his evidence by writing and drawing on a court whiteboard and the trial was conducted in simplified language because of his brain injury.
Prosecutor Duncan Penny KC said in his closing speech that de Zoysa "had hidden the gun and was carrying it on the streets in a holster" on the night of the shooting.
"In the cell Louis De Zoysa knew he was about to be searched," said Mr Penny.
"He produced the gun behind his back. He twisted his body in order to get his right hand in a place where he could aim the gun at Sgt Ratana.
"Once the gun was pointing at Sgt Ratana Louis De Zoysa pulled the trigger.
"All of these were conscious, deliberate actions. Louis De Zoysa knew what he was doing."
De Zoysa bought the gun an antiques auction, making the bullets himself on the farm where he lived, before hiding the weapon under his coat while he was in the police van.
He'd earlier told police he was carrying cannabis during a stop and search while he was walking to his parents' home, but didn't disclose that he was carrying a gun while also lying by saying the bullet weren't real.
Footage from inside the police van shows how close he came to being discovered with the weapon which he covertly removed from a holster concealed on his left side just yards from officers.
A rear-facing camera mounted on the van filmed a reversed image of the 25-year-old's empty left hand as he exited the vehicle - with the gun in his non-dominant right hand already hidden under the rear vent of his overcoat.
Jurors were later given the chance to fire the revolver at the ceiling themselves in court to see how difficult it was to pull the trigger, and spent five hours deliberating after being sent out on Thursday afternoon.
Analysis of De Zoysa’s devices revealed an interest in weaponry and violence including right wing extremism, Islamic extremism and homophobia.
Defence for de Zoysa, however, claimed the gun had fired by mistake - which lab tests later disproved - and that he had been suffering an autistic meltdown at the time.
De Zoysa had claimed he was stuttering with fear and "hyperventilating" as he was taken through a tunnel into the custody suite, and asked police officers if they were going to "zap" him when he was taken into the police station.
He also said he had been "sad" to learn Sgt Ratana had died, pleading not guilty as he claimed not to understand what "guilty" meant.
De Zoysa had claimed he was stuttering with fear and "hyperventilating" as he was taken through a tunnel into the custody suite on the night in question.
He asked police officers if they were going to "zap" him when he was taken into the police station, and later said he hadn't disclosed he was carrying a gun as he was feeling "anxious".
Mr Penny hit back at these claims in his closing remarks, saying: "He understood what it meant to fire live ammunition.
"The evidence suggests he was not having an autistic meltdown.
"The key actions in the killing of Sgt Ratana were purposeful and they were deliberate."
Sgt Ratana was a veteran officer and father of one originally born in New Zealand, who the court heard was planning to propose to his partner of six years, Su Bushby, when he died.
Police watchdog IOPC who later probed the case found the arresting officers had no case to answer for misconduct.
Following the verdict on Thursday, de Zoysa nodded twice before was remanded into custody at the court, where he will be sentenced at a later date.
Sgt Ratana's partner, Su Bushby, and Metropolitan Police Commissioner Sir Mark Rowley were among those in the public gallery as the verdict was returned.
