A 54-year-old has been arrested in relation to the murder of patched Tribesmen Motorcycle Club member John Henry Harris.
Mr Harris had been dropped at the Whangarei St John Ambulance station last October after being shot in the chest, and died shortly after.
A 41-year-old man has since appeared in court charged with his murder, jointly charged with two other men. In April, police were still looking for the third man.
A 19-year-old man and a 21-year-old woman have also been charged with being accessories after the fact.
A 54-year-old man was arrested in Tinopai, in Northland, during a police operation on Wednesday.
He's due to appear in the Whangarei District Court on Thursday.
The charges he will be facing are not yet known, a police spokesperson told Newshub.