GEM COUNTY -- The family of a Kuna man believed to have been swept away in the Payette River says they have recovered items that belonged to him about 15 miles downstream from the spot they think he crashed into the water.

Jerry Coburn, 43, has been missing since May 7, when he did not return home from a fishing trip to Valley County. Family members say Coburn would have been headed north on Idaho 55 in his blue pickup at about the same time another driver saw a northbound blue pickup veer off the road and into the fast-moving river.

MORE: Family fears Kuna man was in pickup that plunged into Payette River

Searchers have not found the pickup or the driver. Without that, the Boise County Sheriff's Office says, they can not confirm that Coburn was the man who went into the river.

But Coburn's family, including step-brother Michael Taggart, say they have no doubts Coburn was the victim.

Their fears were amplified Sunday, when items that belonged to Coburn were found in the Black Canyon Reservoir, which the Payette River feeds into.

Taggart said searchers found a fishing pole and a red coffee mug with a Flying J logo that belonged to his brother. A vehicle headrest discovered floating in the water also likely came from Coburn's pickup, he said.

READ: Search for pickup in Payette River turns up empty

The Boise County Sheriff's Office has suspended its active search for the pickup and its occupant, but Coburn's family has been searching daily since he went missing.

Anyone with information that could aid the search is urged to contact Boise County dispatch at 208-392-4411.