Man found guilty of murdering police sergeant after smuggling gun into custody

Louis De Zoysa retrieved a loaded revolver from a hidden holster up to 16 minutes before opening fire at point-blank range on Sergeant Matt Ratana.
De Zoysa concealed the weapon as he was transported to the police station and searched, then fired four shots at Ratana in a holding cell, killing him.
De Zoysa was found guilty of murder after claiming he suffered an "autistic meltdown" and did not mean to pull the trigger.
The case has prompted UK police forces to increase security screenings and issue more officers handheld metal detectors.
De Zoysa had a stockpile of antique and replica firearms as well as ammunition in his rented accommodations.