Police in Washington state suspect that the father wanted for allegedly killing his three daughters might not be alive in the remote wilderness.

The Wenatchee Police Department reported finding three young sisters, 9-year-old Paityn Decker, 8-year-old Evelyn Decker, and 5-year-old Olivia Decker, deceased near Rock Island Campground on June 2.

Police suspect that Decker killed them during a planned visitation and then fled the area.

The Kittitas County Sheriff’s Office announced on Monday night that there is no definite evidence of Decker’s current whereabouts or if he is still in the area, yet the search continues throughout Teenaway Valley and Liberty.

According to FOX News Digital, early promising leads have dwindled over the past two weeks of searching. Nonetheless, the department emphasized, “We cannot and will not give up on this search.”

According to the Wenatchee Police Department, the girls’ mother reported them missing on May 30 after they left their central Washington home for a scheduled custody visit with Decker.

“U.S. Marshals are following up on leads, and we continue to conduct joint operations with (nearby) Kittias County,” Chelan County Sheriff Mike Morrison told USA  TODAY. “Additional air operations will take place over the next couple of days inserting specialized search teams into more inaccessible areas.”

The sheriff added that a cadaver dog will join in the search this week.

Meanwhile, the U.S. Marshals Service announced a reward of up to $20,000 for information that leads to Decker’s arrest.

Decker is described as a white male who stands 5 feet, 8 inches tall and weighs around 190 pounds. He has black hair and brown eyes, and was last seen wearing a light-colored shirt and dark shorts.

“Due to safety concerns, do not attempt to contact or approach Decker,” police previously said of Decker, who has extensive military training.

Anyone with information on his whereabouts is urged to contact the CCSO tip line at 509-667-6845, or submit information online at https://www.co.chelan.wa.us/sheriff/forms/submit-a-tip.

Check back for updates.

[Feature Photo via Whitney Decker/Facebook]