Authorities have uncovered bones in the latest manhunt for fugitive dad Travis Decker, the prime suspect wanted in the murders of his three young daughters. 

The two-day sweep of campgrounds near Leavenworth, Washington – which involved more than 100 FBI agents alongside local law enforcement – concluded Tuesday and yielded the first major development in a nationwide hunt that has gripped the public since early summer, Fox 13 Seattle reported. Decker, an Army veteran with extensive survival training, has managed to elude capture for three months.

Investigators have been searching for Decker since June 2, when he failed to return his daughters –  Paityn, 9, Evelyn, 8, and Olivia, 5 – to their mother after a scheduled visitation. The children’s bodies were later found near Rock Island Campground along Icicle Creek with bags over their heads. Autopsies determined that the children died from suffocation and ruled the manner of death a homicide. 

While initial assessments could not confirm whether the bones were human, the items were sent for forensic testing to Central Washington University’s anthropology department to determine if they may be linked to the search for Decker, Fox 13 reported. 

Travis Decker is accused of killing his three young daughters and leaving their bodies at the bottom of a hill at a Washington state campsite. (Courtesy of Chelan County Sheriff’s Office)

So far, authorities have searched 247 acres in three major sweeps, Fox 13 reported.

Chelan County Sheriff Mike Morrison told that station that additional campground and trail closures are likely as investigators continue to expand their search efforts. 

The entrance to Rock Island Campground where multiple law enforcement agencies are participating in the search for Travis Decker on Monday and Tuesday. (FBI via AP)

Another large-scale search, coordinated with federal partners, is planned for September, the outlet added, citing the sheriff.

The FBI and Chelan County Sheriff’s Office did not immediately respond to a request for comment from Fox News Digital.