The man accused of the Family Court bombings and alleged murders in Sydney in the 1980s has been remanded in custody after facing court on 32 charges, including four counts of murder.

Leonard John Warwick was arrested yesterday at Campbelltown in Sydney's south-west, suspected in a series of attacks on members of the judiciary and the public between 1980 and 1985.

The attacks between 1980 and 1985 included:

the fatal shooting of his brother-in-law, Stephen Blanchard, in 1980;

the fatal shooting of his brother-in-law, Stephen Blanchard, in 1980; the fatal shooting of judge David Opas in 1980;

the fatal shooting of judge David Opas in 1980; the bombing of the home of another judge in 1984;

the bombing of the home of another judge in 1984; the bombing of the Parramatta Family Court in 1984;

the bombing of the Parramatta Family Court in 1984; the bombing of the home of Judge Ray Watson, killing his wife, in 1984; and

the bombing of the home of Judge Ray Watson, killing his wife, in 1984; and the bombing of a Jehovah's Witness church hall, killing Graham Wykes and injuring other churchgoers, in 1985.

A previous coronial inquest heard evidence Warwick had a long-running dispute with the Family Court related to a custody battle with his estranged wife.

A bomb attached to the door of their family home killed Pearl Watson (right), wife of Judge Ray Watson. ( Supplied: Watson family )

Police facts tendered to the court today revealed allegations that Warwick was heard to make threats about Family Court judge David Opas, before his murder.

Warwick's former wife Andrea told police that during an adjournment at their Family Court proceedings in May 1980, Warwick told her, "you don't have to worry about him anymore because he won't be around much longer".

"Andrea understood that the accused was talking about Judge Opas," the police facts state.

"Shortly after 7:00pm on Monday, 23rd June 1980, Judge Opas was shot dead at the front of his home at Woollahra."

Leonard John Warwick in court in Sydney. ( ABC News: Vincent de Gouw )

The police facts also alleged that Warwick completed a welding course in 1979 and showed a family friend how to make "beer bottle bombs".

Police said Warwick told the friend not to tell anyone else how such bombs were made.

In reference to the bombing of the Family Court at Parramatta in April 1984, police say Warwick "possessed the skills to create a pipe bomb through his knowledge of explosives and welding skills".

His semi-rural property at Douglas Park, in Sydney's south-west, was searched by dozens of police officers yesterday.

They appeared to be sifting through the contents of his home, garage and a large shed.

Among the items examined were a boat, at least one vehicle and numerous boxes strewn across the property's lawns.

New technology helped solve cold case

Police said the arrest followed the reopening of their investigation in 2012 and the use of technology that had not been available at the time of the crimes.

"The reality is that we have things that are available to us today that simply didn't exist 30 years ago," NSW Police deputy commissioner Nick Kaldas told 7.30.

Sorry, this video has expired An ABC TV report from 1987 shows the destruction

"Both in terms of information management, as I mentioned, fingerprints, DNA - all of that stuff was not available to investigators 35 years ago."

Detective Chief Inspector Pamela Young from the unsolved homicides team said they were pleased to ring a few victims and their families yesterday to deliver the news and hoped it has brought satisfaction.

"There have been dangers associated with this case, hence we haven't announced what we're been doing along the way... I imagine a few people are surprised about what's happened," Detective Chief Inspector Young said.

She said DNA technology was part of the brief of evidence among new witnesses statements.

"Real witnesses have given evidence that were not identified before, witnesses who gave scant evidence before due to methods of recording or their confidence in coming forward in such a dangerous situation, they've expanded their evidence," Detective Chief Inspector Young said.

Pearl Watson, wife of Judge Ray Watson, was killed by a bomb blast the family's home. ( ABC News: Peter Ryan )

"Speaking generally, criminals at that time weren't as cautious as they are now and that has helped us."

The daughter of Judge Watson, whose wife Pearl was killed in one of the attacks, said she was very grateful.

"I'm still in a state of shock and I'm totally churned up inside, but in a way I'm very, very relieved, and I think it's about time the person concerned was brought to justice," she said.

Family Court Chief Justice Diana Bryant said in a statement she was grateful police had "at last made an arrest after so long without any resolution of these crimes".

Police have urged anyone "who may have been reluctant to come forward with information beforehand" to do so now.

A Jehovah's Witness church hall was bombed in 1985. ( ABC News )

Warwick's charges include murder; attempted murder; destroying or damaging a building by explosive with intent to murder; breaking, entering and committing a felony in a house of worship and 13 counts of burning or maiming by maliciously exploding another substance.

Warwick's lawyer, Sarah Crane, told magistrate Robert Rabbidge her client was not required in court but the magistrate disagreed, saying it was in the public interest that he be brought up.

He appeared calm during his brief appearance in Campbelltown Local Court today and sat quietly in the dock.

Ms Crane did not apply for bail on behalf of her client and it was formally refused.

He is due to appear in court again on the August 6.