The Crown says two men charged with murdering an undercover policeman were on a homicidal mission when they chased him down and shot him three times in September 2008.
John Skinner and Iain Clegg are on trial in the High Court at Auckland accused of killing Sergeant Don Wilkinson and attempting to murder another officer, identified as Officer M.
The policemen had been attempting to covertly install a tracking device on Mr Skinner's car when they were discovered.
In his closing address, Crown lawyer Simon Moore told the jury on Tuesday that the accused took the law into their own hands, engaging the two officers in a one-sided stoush.
He said Iain Clegg and John Skinner had what he called the "wonderful benefit" of being armed, and described them as cold, calculating and violent.
Mr Skinner's claim of memory loss surrounding key events that night was very convenient, Mr Moore said.
Mr Skinner gave evidence last week saying it was his intention only to confront the two policemen and find out why they were on his property.
But Mr Moore reminded the jury of Officer M's testimony in which he said Mr Skinner was not interested in an explanation.
He said instead the accused shot the two policemen in a coldly efficient manner.