WANTED: Authorities search for homeless dad suspected of killing his three daughters in Washington State

A multi-agency manhunt has been launched for Decker. He is described as white, 5 feet 8 inches tall, 190 pounds, with black hair and brown eyes. He was last seen wearing a light-colored shirt and dark shorts, according to police.

Whitney Decker, the mother of the three young girls, reported her daughters missing on Friday at 9:45 pm, informing police that her children never returned from a planned visit with their father, Komo News reported. Travis was believed to have been living out of a white 2017 GMC Sierra pickup truck and was traveling westbound on Highway 2, Wenatchee police said.

On Saturday, Washington State Patrol (WSP) issued an Endangered Missing Person Alert (EMPA) for Paityn, 9, Evelyn, 8, and Olivia, 5.

Wenatchee police detectives obtained a warrant for Decker's arrest for three counts of first-degree custodial interference. Investigators suspected, with the help of information from Wenatchee PD, the FBI, and the Chelan County Sheriff's Office (CCSO), that Decker and his girls were still in Chelan County.

On Monday, the search narrowed between Icicle Road and Chumstick Road near Leavenworth, a city located just a few miles west of Wenatchee, police said. A CCSO Forest Service deputy discovered Decker's truck around 3:45 pm, about 17 miles up the road while patrolling on a motorcycle. The deputy found the three children, dead inside Decker's truck, but Decker was not at the scene.

A large-scale 24-hour search operation is ongoing to locate Decker, which includes the East Cascade Regional SWAT Team, US Border Patrol Tactical and Search Trauma Rescue teams, and the Department of Homeland Security.

Authorities said Decker has extensive military training and told the public not to approach him if seen, but to immediately contact 911. Police do not know if he is armed. Anyone who has seen Decker since May 30 is asked to contact the police.

The three sisters all attended Lincoln Elementary School. Kory Kalahar, Superintendent of the Wenatchee School District, posted a statement on the district's website, saying, "I understand how distressing this news is, and the questions many of you undoubtedly have. Our immediate and utmost priority is the well-being of the Lincoln Elementary community. We are focusing all our efforts on providing comprehensive support to their students, staff, and families during this unimaginable time."

A GoFundMe has been created to support Whitney Decker as she navigates through this tragedy.