Three days later council workers found his bullet riddled body dumped in bushland off the Pacific Highway at Cowan, north of Sydney.

It is not known exactly how long his body had been there but no effort was made to conceal it, police say.

More than six months later, police released footage of a white van they believe could be connected to the 37-year-old's shooting death.

The white van was seen in the nearby suburb of Berowra early in the morning of Friday, June 26, 2015 – just hours before Mr Easter's body was discovered.

Detectives have also revealed they believe the father-of-one was shot elsewhere before being driven to Cowan and dumped.

Mr Easter's body was discovered one week after his associate John Weston was charged with the murder of Summernats judge Laurie Starling

Close friend Angus McGuffie said at the time he was "shattered" his close mate had been killed and wanted him remembered as a loving father, an honest man and fitness fanatic.

"He wasn't afraid to be a dag to make his son laugh - the bond they had was unbreakable. He wasn't a bad person," Mr McGuffie said.

"Anyone who knew Mark wouldn't have one bad word to say about him … every memory I have with [him] is nothing but good times and [his] ridiculous laugh. He welcomed everyone and anyone and treated everyone with respect," he said.

"And I know he loved Biancha [his partner] more than anything."

Another close friend told Fairfax Media his death should not be automatically linked to his appointment as Sergeant at Arms of the gang's City chapter.

Mr Easter was formerly a member of the Nomads.

Police said they were keen to speak to anyone who saw or knew of Mr Easter's movements between when he was last seen at 8.40pm on June 23 to the day his body was found on June 26.