Travis Decker, the Washington state man wanted in connection with the deaths of his three daughters, was possibly spotted in Idaho over the weekend, and federal authorities are following up on the new lead after the father has been missing for over a month.

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 Decker.

Authorities asked anyone who was in the area over the Fourth of July weekend, specifically in the Bear Creek area in Idaho, to come forward with any tips, CBS affiliate in Seattle KIRO-TV reported. 

The Bear Creek area is between Sawtooth National Forest and Boise National Forest, about 100 miles east of Boise, Idaho.

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. 

Authorities found the girls’ bodies down an embankment at a campsite in the Cascade Mountains. A man’s blood discovered on the tailgate of Decker’s vehicle was confirmed to likely be his, with the DNA profile matching the one found on his belongings, the Chelan County Sheriff’s Office said last week.

The discovery came three days after he failed to return the girls to their mother’s home in Wenatchee, about 100 miles east of Seattle, following a scheduled visit.

Last month, investigators said there was no evidence that the father and ex-soldier remained in the area or that he is alive at all. They also released images of what Decker might look like after weeks on the run.

Authorities in Washington on June 10 said they believed they’d spotted Decker 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 residents and people camping or recreating in the area. He said Decker has a history of hitchhiking and encouraged motorists not to pick up any hitchhikers.

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