On May 4, 1949, the then largest Hong Kong Police vessel, Police Launch No.1 departed from the Marine Police dockyards to head into Mirs Bay, northeast Hong Kong for its regular patrol mission. At the time, the Hong Kong-Chinese border was an extremely dangerous place, there were many cases of pirate attacks, armed thugs and even communist militias crossing the border to kill police officers and taking their weapons. As a result, officers stationed at the border were very heavily armed, inspectors stationed there were even trained to use Bren guns, grenades and 3-inch mortars. In this instance, however, it would be two officers who launched the attack.
The launch was commanded by a British inspector and a sub-inspector, with 21 crew members on board. Around 2 a.m. on May 6, two of the crew members, the mutineers arrived to their duty post, which was to guard the armoury keys. Half an hour later, they unlocked the armoury and each took a Bren gun. They first destroyed the radio system, then they sneaked into the officers quarters and killed the two inspectors. They then advanced into the cabins and locked al the crew members in there, then, they forced one of the helmsman to the cockpit. Meanwhile, the now highest-ranking officer, a corporal heard the commotion and loudly asked what's going on, and was immediately shot dead. The other helmsman on duty attempted to resist but was gunned down as well. The mutineers then attempted to locate the boatswain which they had beef with but failed, and they turned to looting their colleagues.
The launch was then sailed close to the border, but the ship was beached before they could cross it. As a result, they locked the helmsman back into the quarters and tooke whatever valuables and weapons they can take. They then fled northeast across the border. Reports indicated that two Bren guns, five rifles (likely Lee-Enfields) and five pistols (likely Webley revolvers) and ten crates of ammo were taken. The police issued a bounty of 20,000 HKD (100k to 190k USD in today's value) for the mutineers' capture. There were news that some involved people were arrested but unfortunately there were no detailed records of it.
7 years later, in 1956, an armourer with the Royal Electrical and Mechanical Engineers Command Workshop in Kowloon discovered a Bren gun with the serial number "HKP004". After contacting the Hong Kong Police, it was confirmed that this was one of the Bren guns taken from Launch No.1. Turns out in 1953, British troops in Korea was able to recapture the gun on the battlefield, due to the necessity of arms, the gun was kept in theatre and was used by three different regiments before being returned to Hong Kong. The Bren gun was then returned to it's rightful owner and was put on display in the Police Museum.
P.S. The exhibit of the Bren gun claimed that the Launch was attacked by pirates but newspaper reports at the time was very clear that it was a mutiny of two crew members.