Andrew Russell, 34, appear in Gosford Local Court on Thursday charged with murder, attempted robbery while armed with a dangerous weapon, and two counts of assaulting an officer in the execution of duty.

Russell, 34, was arrested outside a fast food restaurant on the Central Coast just before 2pm on Wednesday, following a four-day manhunt.

Two others alleged to be involved in the crash are still wanted by police.

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Russell did not apply for bail. The case against Russell was adjourned to Wollongong Local Court on July 17 when he is due to appear by video link.

Police allege Mr Russell, along with Darren Butler, 27, and Holly Green, 25, were inside a Toyota Corolla that chased another car on the Princes Highway at Albion Park Rail.

The second car crashed into the rear of a petrol tanker about 2.20am on Saturday. The crash killed 27-year-old Mr Merrett.

Police inquiries suggested the car he was a passenger in, driven by his sister, may have been pursued by another vehicle at the time of the accident, and shots may have been fired.

Mr Merrett's sister and two other passengers, a man and a woman, both aged 25, were hospitalised with serious injuries.

Their conditions are stable.

Officers from Lake Illawarra Police District established Strike Force Warrane to investigate the circumstances surrounding the incident.

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Following inquiries, officers from Brisbane Waters Police District arrested Russell and a 25-year-old woman unconnected with the crash outside a fast food restaurant in Lisarow on the Central Coast.

The female was charged with shop lifting, assaulting police and skipping bail over unrelated matters.

Police are still searching for Darren Butler and Holly Green, and are urging anyone with information to come forward.

The public is advised not to approach. Call Crime Stoppers on 1800 333 000.