The BriefThe FBI found bones while searching for Travis Decker in Leavenworth forest, though their origin is currently unknown.Decker is wanted for allegedly killing his three daughters at Rock Island Campground in June.A $20,000 reward is offered for information leading to Decker's arrest; he is considered armed and dangerous.WENATCHEE, Wash. - The FBI reportedly found bones while searching for Travis Decker in a large area of the Leavenworth forest, sources tell FOX 13.What we knowA multi-day shutdown near the Rock Island Campground resulted in the recovery of possible evidence in the case of Travis Decker, who is accused of killing his three daughters at the same site several months ago.AdvertisementAdvertisementAdvertisementAdvertisementOne of the recovered pieces of evidence included bones, according to the Wenatchee World."[Chelan County Sheriff Mike Morrison], he shared that the FBI found bones in the 200-mile-acre area they searched near the Rock Island Campground off Icicle Road near Leavenworth," said Jenni Rodas with the Wenatchee World.FBI searches for Travis Decker near Rock Island Campground (via FBI)Rodas told FOX 13 Seattle that detectives aren't sure whether the bones found this week belong to an animal or human. They will undergo testing at the Washington state crime lab."According to Morrison, earlier in the search, they found remains of what appear to be an overdose victim," Rodas said.Dig deeperAdditionally, Chelan County Sheriff Mike Morrison also said he expects the FBI to conduct more searches in the area in September.AdvertisementAdvertisementAdvertisementAdvertisementThe FBI has yet to specify what items were recovered during the operation, which covered more than 1 million square meters of dense terrain.Travis Decker is wanted in the deaths of his daughters Paityn, 9, Evelyn, 8, and Olivia, 5. The girls were found dead at the Rock Island Campground on June 1, and authorities have been searching for Decker ever since.The U.S. Marshals Service is offering a reward of up to $20,000 for information leading to Decker’s arrest. He is considered armed and dangerous.The SourceInformation in this story came from the Wenatchee Wold, FBI Seattle, the Chelan County Sheriff's Office and FOX 13 Seattle reporting.Washingtonians among 19 charged in major drug operation tied to Sinaloa cartelAdvertisementAdvertisementAdvertisementAdvertisementWA Border Patrol agents arrest 2 firefighters battling Bear Gulch FireTeen arrested after bringing gun to Graham-Kapowsin High School in WA19-year-old accused of trying to kidnap bikini barista in LakewoodSeattle Seahawks drop team's 'Rivalries' uniformTo get the best local news, weather and sports in Seattle for free, sign up for the daily FOX Seattle Newsletter.Download the free FOX LOCAL app for mobile in the Apple App Store or Google Play Store for live Seattle news, top stories, weather updates and more local and national news.