A former firefighter accused of a string of Sydney bombings and murders in the 1980s allegedly told his ex-wife a Family Court judge "won't be there much longer" weeks before he was shot dead.
Opening the crown case on Tuesday, prosecutor Ken McKay said when the ex-wife asked if the judge was going on holidays, Leonard John Warwick replied: "No, he won't be there at all."
The crimes involved extreme, targeted violence, the prosecutor told Justice Peter Garling, who is hearing the trial without a jury.
They took place when Warwick's Family Court matters were proceeding and the victims had intervened in the dispute with his ex-wife, he said.
Warwick, 71, has pleaded not guilty in the NSW Supreme Court to four murders - including the shooting deaths of his brother-in-law and a judge - and 20 other offences relating to seven events which occurred between February 1980 and July 1985.
He was involved in a long-running Family Court dispute which ended in 1986 and "inextricably linked" him to the seven events and provided him with a motive, the crown alleges.
Warwick is charged with the 1980 shooting murders of his brother-in-law Stephen Blanchard and Justice David Opas; the bombing of Justice Richard Gee's home and of the Family Court building in Parramatta in 1984; and, in the same year, the bombing of the home of Justice Ray Watson in which his wife Pearl was killed.
His ex-wife's solicitor was allegedly the target of a car bomb.
Warwick in 1985 allegedly set off a bomb that ripped apart a Jehovah's Witnesses hall, killing Graham Wyke and injuring 13 people, part of the congregation offering support to his ex-wife Andrea Blanchard.
In his brief defence opening, lawyer Alan Conolly described his client as "a lover not a murderer". He said the crown evidence was "flimsy".
"There was not one scintilla of evidence against this man except some DNA which the defence will say has been very poorly cared for," Mr Conolly said.
Mr McKay said the body of Warwick's brother-in-law was found in a creek in a national park days after he went missing.
He had been shot in the head while 11 bricks were roped around his waist - bricks which were similar to those found at Warwick's home.
Justice Opas had made orders and comments which Warwick would have regarded as being adverse to his case, the prosecutor said.
Warwick allegedly told his ex-wife: "You don't have to worry about him anymore. He won't be there much longer."
The judge was shot dead in the courtyard of his home with a .22 calibre rifle which was the same type used to kill Mr Blanchard, Mr McKay said.
Justice Gee replaced Justice Opas in hearing the case and a bomb exploded at the front of his house early one morning. It destroyed the building.
Justice Watson had been about to leave for work when his wife opened the door and was killed by an explosive.
Mr McKay said Warwick's father had worked at a colliery using explosives and detonators for decades while the accused had been in the army from 1967 to 1969.
The trial will continue on July 9.