In a statement after Mr Hines' arrest, police said they remained focused on the case, dubbed Operation Palm, and were committed to finding answers for his loved ones.
"This further arrest is a credit to the dedicated investigation team who have worked tirelessly over the past year-and-a-half. We would like to thank the members of the community who contacted police and provided information which assisted with our inquiry."
Police are still encouraging anyone with information relating to the case, dubbed Operation Palm, to call 0800 OP PALM or pass their information on anonymously via Crimestoppers on 0800 677 256.