A helicopter search failed to find any signs of a missing Broomfield treasurer hunter who disappeared while searching for a $2 million cache of gold, jewels and artifacts.

The Associated Press reports a helicopter flight this week by New Mexico State Police and the state’s search and rescue team turned up nothing, but Randy Bilyeu’s relatives say they’re not giving up.

A father and grandfather, Bilyeu has been missing for more than a month since he set out in January in search of author Forrest Fenn‘s treasure.

Bilyeu’s dog and raft were found along the Rio Grande. There has been no sign of him.

His ex-wife, Linda Bilyeu, says there are areas that can still be searched with drones. She says she’s thankful for the volunteer searchers but doesn’t want to put anyone in danger.

Bilyeu’s interest in coins and artifacts was driven by author Fenn’s treasure book, “The Thrill of the Chase.”