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The killing of Senior Constable Len Snee bears haunting similarities to three other police deaths in the line of duty.
Mr Snee was shot dead on Thursday as he attended what police described as a low-level routine cannabis bust.
His killer, Jan Molenaar, modelled himself on Rambo - the monosyllabic 1980s military man made famous by actor Sylvester Stallone.
Friends said Molenaar, a former Territorial Army soldier, was a "dab hand" with guns and explosives - a loner with few close friends.
Gun control advocate Professor Philip Alpers said researchers characterised such types of offenders as "pseudo-commandos", given to fantasy, dressing in camouflage or black, with an obsessive fascination with firearms, preferring semi-automatic military-style weapons.
"It is very common in the United States. There's a lot of copycating going on amongst pseudo-commandos. They are very often found to have clippings on their bedroom walls of previous shootings. They were obviously fantasising about them.
"One thing that's very common is a fascination with firearms and with all the things that come with that - the right to keep and bear arms, the fear of government, the hatred of police, anti-authoritarian.
"Exactly the type of people who disobey gun laws are the people who are most likely to cause damage like this."
Three other police officers have died in situations where sieges and an obsession with guns featured in the tragedies.
Sergeant Stewart Guthrie, 41, was one of 13 killed by David Gray in 1990 at Aramoana during a 23-hour rampage. A loner, Gray used a Norinco AK47.
Six years later, former territorial soldier Terence Thompson, 43, shot dead Constable Glenn McKibbin in Flaxmere. In 2002, teenager Daniel Luff shot dead Feilding detective constable Duncan Taylor. During a four-hour siege, he boasted to negotiators that if anyone tried anything they would suffer.By Yvonne Tahana Email Yvonne