The lawyer for accused Family Court bomber Leonard John Warwick has described the case against him as lame, absurd and ridiculous.

"The idea that he could have by himself constructed the bombs is absurd, and the evidence that he had the expertise comes out of Monty Python," Alan Connolly told the Supreme Court.

Warwick, 71, appeared on a video link for his judge-alone trial charged with shooting dead his brother-in-law and Justice David Opas.

Leonard John Warwick has been accused of bombing attacks. (AAP) (AAP)

He is also accused of killing Justice Ray Watson’s wife Pearl Watson and Graham Wykes in separate bombings.

Justice Watson and Justice Richard Gee’s homes were both bombed in the 1980s, along with the Family Court at Parramatta and a Jehovah’s Witness hall.

Warwick has pleaded not guilty to more than 20 offences, and his lawyer has told the court the events are unconnected.

“Why ever would Mr Warwick have had anything to do with the atrocious, violence reckless event?" she said.

"And he couldn’t have anyway, he didn’t have the skills, he didn’t have the time, and he didn’t have the motivation."

Police search the property and family home of Leonard John Warwick in Douglas Park, NSW, in 2015. (AAP) (AAP)

Mr Connolly said they would discredit the Crown’s bomb expert and police who had bungled the case.

He argued there were other possible perpetrators including a well-known criminal identity.

The Crown has alleged Warwick committed the crime because of an ongoing battle with his ex-wife over custody of their child and their former home, an allegation Mr Connolly rejected.

"He was a resolute dedicated father who was considered even by his ex-wife to be a good father," he said.

Former Family Court Judge Josephine Maxwell was the Crown’s first witness and spoke of having police guards in her home 24 hours a day for the next 18 months.

Ms Maxwell was also named in a threat after her colleagues were targeted and the Parramatta building was bombed.