Profilers say the killer of Wellington woman Mei Fan was a meticulous planner.
Police have still to catch whoever stabbed the mother of two to death in her Miramar home four months ago.
Detective Senior Sergeant John van den Heuvel told Newstalk ZB the murder was carefully executed.
"This crime was very well planned and prepared for, and it's likely that Mei's killer has discarded of items, which could be items of disguise, shortly after leaving the address."
Wellington police are following up new tips from the public, after details of the case were aired on Police 10-7 last night.