BOISE — Federal authorities in Idaho are following up on a possible sighting over the weekend of a Washington state man wanted in connection with the deaths of his three daughters.

The U.S. Marshals Service Greater Idaho Fugitive Task Force said it had received a tip Saturday from a family recreating near a camping area in Idaho’s Sawtooth National Forest that they saw a man whose description was consistent with that of Travis Decker.

Decker has been wanted since June 2, when a sheriff’s deputy in Washington found his truck and the bodies of his three daughters – 9-year-old Paityn Decker, 8-year-old Evelyn Decker and 5-year-old Olivia Decker – at a campground outside Leavenworth, Washington. The discovery came three days after he failed to return the girls to their mother’s home in Wenatchee, about 100 miles (160 kilometers) east of Seattle, following a scheduled visit.

Authorities in Washington on June 10 said they believed they’d spotted Decker, a former soldier, near a remote alpine lake in a popular backpacking area in the Cascade Range. Tracking teams followed up on a tip from hikers who reported seeing a lone hiker who appeared to be ill-prepared for the conditions.

But he has not been found.

Eric Toms, supervisory deputy U.S. Marshal with the District of Boise, said the agency was receiving more tips from the public following the statement the task force released Sunday. Toms in an email said the agency was evaluating each tip and that a search team involving the marshals service, the U.S. Forest Service and the Camas County Sheriff’s Office set out Monday.

He said authorities planned to speak with local residents and people camping or recreating in the area. He said Decker has a history of hitchhiking and encouraged motorists to not pick up any hitchhikers.

Toms said search efforts Monday were being conducted by air and on the ground, including by dirt bike. He didn’t have any additional information to immediately release.

The forest area is nearly 600 miles (965 kilometers) from the lake where authorities were searching last month.

Jason Knight, who is the director, co-founder and an instructor at Alderleaf Wilderness College in Monroe, Washington, described the terrain in the region where authorities were searching as rugged and challenging, with often significant temperature variations between day and night.

In the summer months, it’s possible to forage and fish, and if someone is trying to avoid attention, they might raid campground sites or search trash cans outside of towns, he said.

The Marshals Service is offering a reward of up to $20,000 for information leading to Decker’s capture.