Five police divers are searching the Turakina River for clues about missing man Brett Hall.
The search was "part of ongoing inquiries" and was "a result of developments from last week", said Detective Senior Sergeant Dave Kirby, the Whanganui Police officer in charge of the investigation.
"We're looking for items believed to have been discarded into the river," Mr Kirby said.
The search, which started yesterday morning, is expected to finish today.
Mr Hall disappeared three years ago. He was last seen at his Pitangi property, between Parikino-Atene, on May 27, 2011.