Five Nelson detectives will spend next week on the West Coast trying to solve the two-year-old riddle of what happened to goldminer Hugh McAllister.
The 70-year-old from Kumara was reported missing in January 2010.
Land, air and river searches were carried out, including checks of abandoned mine shafts in the old Greenstone goldfield, but all failed to turn up any trace of the missing man, although two days later his abandoned ute was found concealed with a $15,000 stash of gold inside.
Conjecture has been rife in the two years since his disappearance, the McAllister family fearing that he may have been murdered, while others speculated that he staged his disappearance and was now in Australia.
In early March, a former friend of Mr McAllister said he spied him driving south over the William Stewart Bridge, over the Taramakau River, heading towards Kumara, but police were unable to confirm the sighting.