Police are baffled as to how Saturday Lobsang Hassan came to possess a gun or why he turned murderous after being thrown out of the Deslandes pub.

The 30-year-old builder, who was convicted of murdering Darren Deslandes and attempting to murder his brother, had no prior convictions and police could uncover no criminal past in their background checks on him.

Detective Chief Inspector Gordon Allison, who led the investigation, said: “Someone who can source a firearm in that period of time, you would think they had some contacts in the criminal world. “Hassan has never been on our radar. He was a builder, he was jobbing in regular employment.”

He said Hassan had patronised the pub once or twice but did not know the brothers. He was at the annual New Year’s Eve party, which the Deslandes threw for family, friends and regulars, with another person.

Judge David Paget told the court Hassan enjoyed the “trappings of a gangster”, he had access to a semi-automatic, fully loaded pistol and drove a BMW 4x4.

He said to Hassan: “You have no convictions but you appear to be someone who at least admires that style of life.”

D Chief Insp Allison said: “I am pleased the family has got some sort of justice. They are not typical of Trident victims. They are ordinary people who got caught up with a maniac who had a gun.”