A Sydney man has appeared in court over an infamous series of fatal shootings and bombings targeting the Family Law Court three decades ago, with police confident DNA evidence will prove who was behind them.

Detectives arrested Leonard John Warwick, 68, yesterday in connection with the notorious cold case.

The former firefighter was taken to Narellan police station after he was arrested by detectives from Strike Force Reddan around 11.30am yesterday.

The 68-year-old was arrested this morning in Campbelltown. (NSW Police)

He was later charged with 32 offences, including four murder charges.

Dozens of officers raided a property in Douglas Park yesterday afternoon as they executed a search warrant, at the same time NSW Police were conducting a press conference hailing the work of investigators.

The arrest followed new advances in forensic technology over the past 30 years, as well as fresh witness testimony.

It comes more than three decades after the series of bombings and shootings that targeted judges and the Family Law Court in Parramatta.

In February 1980, Warwick's brother-in-law Stephen Blanchard was allegedly shot dead at his Revesby home, while Justice David Opas was allegedly shot dead at his Sydney home just months later after an adverse ruling against the accused.

A bomb also blew apart the Belrose home of Justice Richard Gee - Justice Opas' replacement - but luckily no one was injured.

The raid followed the man's arrest in Campbelltown this morning. (9NEWS)

Soon after, Jehovah's Witness minister Graham Wykes was killed by an alleged bomb attack on a church hall.

Mr Warwick's wife and daughter had sought protection from the religious group.

Blood drops found at the scene of the bombing 30 years ago were used today as key DNA evidence.

A bomb was detonated at the Family Court in Parramatta in 1984. (9NEWS)

The blood was compared to a sample taken from Warwick's daughter Trudi and found to be "consistent with the paternal lineage".

Police will allege the blood is proof Warwick was behind the bombing and other similar attacks.

Police raided a home in Douglas Park today. (9NEWS)

Four years later, an explosion was allegedly detonated at Justice Ray Watson's home, killing his wife Pearl.

Also in 1984, a bomb went off at the Family Law Court in Parramatta, but no one was injured.

A Sydney man has been arrested over a series of shootings and bombings in the 1980s. (9NEWS)

The spate of attacks sparked a criminal investigation taskforce ordered by then-Prime Minister Bob Hawke.

Yesterday, Deputy Commissioner Nick Kaldas said the developments stemmed from a lengthy police investigation.

"This arrest resulted from a persistent, very tenacious investigation that goes back to early 2012, but in reality goes back 30 years to the 1980s," Mr Kaldas said.

The attacks also targeted the homes of Justices. (9NEWS)

"There is a message here: if you have been involved or if you have information about a murder that may be historic, you need to realise the door will never be closed on a murder investigation.

"It will always be there, and you need to come forward if you have any information."

Detective Superintendent Mick Willing of the Homicide Squad said the work of detectives at the time played a key role in securing the accused's arrest.

The man is facing four murder charges among 32 in total. (9NEWS)

"This is why the unsolved homicide team was set up," Mr Willing said.

"Three years is a long time, but this case goes back 30 years.