(NewsNation) — Authorities have confirmed bones were found during the search for Travis Decker, according to local media reports.

Police have been searching for Decker, who is accused of killing his three daughters — 9-year-old Piatyn, 8-year-old Evelyn and 5-year-old Olivia — during a planned visitation.

The FBI announced Thursday it had completed a two-day search of the Washington state campground where the girls’ bodies were found.

Bones were among the items recovered, Chelan County Sheriff Mike Morrison told local media.

He said the bones were not a complete skeleton, and it was not clear if they were human or animal bones.

The bones were sent to Central Washington University’s anthropology department to be tested to determine their origin.

The bodies of Decker’s three daughters were found in early June near his truck outside of the Rock Island Campground near Leavenworth after he was supposed to return the girls to their mother’s home in Wenatchee.

Decker was nowhere to be found, and his disappearance sparked a manhunt throughout Washington. However, the Chelan County Sheriff’s Office scaled back its efforts in late July due to a decline in new investigative leads.

In late June, authorities acknowledged Decker may have also died while evading law enforcement. They have also advised that he may have changed his appearance in the ensuing weeks to avoid detection.

The U.S. Marshals Service is offering a reward of $20,000 for any information leading to Decker’s arrest.

“This case has shaken the foundation of our country,” Chelan officials said in a statement. “The lives of Paityn, Evelyn, and Olivia Decker were taken in a senseless and unimaginable act of violence. Our hearts remain with their loved ones, and we are unwavering in our commitment to seeking justice on their behalf.”

Officials are encouraging anyone who sees Decker to call 911 immediately and not to approach him, as he is considered armed and dangerous.

The Associated Press contributed to this report.