(WENATCHEE, Wash.) -- The manhunt continued on Wednesday for 32-year-old Travis Decker, who is accused of killing his three young daughters near a campground in Washington, with officials saying he could be "anywhere within the nation."
Paityn Decker, 9; Evelyn Decker, 8; and Olivia Decker, 5, were killed after they left home for a "planned visitation" with Decker at approximately 5 p.m. on Friday, according to the Wenatchee Police Department.
At approximately 3 p.m. on Monday, officials located Decker's vehicle unoccupied near the Rock Island Campground in Chelan County, Washington, police said in a press release on Tuesday. Additional law enforcement officers responded to the scene and found the bodies of the three girls, but "Decker was not located," police said.
There were plastic bags over the heads of each girl and their wrists were zip-tied, according to court documents obtained by ABC News on Wednesday.
Around Decker's vehicle, deputies located zip ties and plastic bags "strewn throughout the area" and the tailgate of the truck had what appeared to be "two hand prints of blood," according to court documents.
A $20,000 reward has been offered for any information leading to Decker's arrest, police said during a press conference on Tuesday evening.
Local officials are working with the FBI, the Department of Homeland Security and the U.S. Marshal's Office in their search for Decker.
"We will not rest until we have located him," Chelan County Sheriff Mike Morrison said during the press conference. "He can be anywhere within the nation, so that's why we have our federal partners on scene helping us bring in additional resources."
Decker, who is homeless and has been living in his vehicle or at various motels or campgrounds in the area, is currently wanted for three counts of first-degree murder and three counts of first-degree kidnapping, police said. He is a former member of the military with "extensive training," but it is unknown whether he is currently armed, officials said.
"Travis, if you're listening, this is your opportunity to turn yourself in, do the right thing, do what you need to do and take accountability for your actions. We're not going to rest, and we're going to make sure we find you. You will be brought to justice, those young ladies deserve it," Morrison said.
Prior to discovering the girls' bodies, police said visitation had been a part of the family's parenting plan, but Decker went "outside the parameters of it which is not normal and cause for the alarm." According to court documents, the parenting plan limited Decker's visitation to every other weekend.
On Wednesday, officials revealed the mother of the girls, Whitney Decker, contacted police on Friday with a civil complaint, saying Decker picked up the daughters at 5 p.m. for a scheduled visitation, but did not return around 10 p.m. She stated that she attempted to call her ex-husband multiple times, but his cellphone was going straight to voicemail, according to court records. Whitney Decker expressed concern because her ex-husband "reportedly has never done this before and further noted he is currently experiencing from mental health issues," the court documents said.
Whitney and Travis Decker were married for seven years but had been divorced for "several years," according to court documents. She recalled moments in their marriage where he would wake her up by "screaming at her in the middle of the night" or randomly leaving her, the court documents said. She also revealed to officials that toward the end of their marriage, Decker was diagnosed with a "borderline personality disorder that she believes he currently does not take medications for."
Prior to the discovery of the girls' bodies, Whitney Decker said in a statement provided to ABC News that she was "concerned" about the safety of her children and she "just wants the girls back home safe and sound."
Detectives later learned Travis Decker and his daughters did not arrive at a "planned 5K running event" on Saturday. Officials believe that Decker traveled to the campground where the girls' bodies were found on Thursday evening and returned the next day with his three children, according to court documents.
When the girls were reported missing, the investigation had not met Amber Alert criteria, officials said, but an Endangered Missing Persons Alert had been issued through the Washington State Patrol. Before the discovery of the girls' bodies, officials said arrest warrants were granted for Decker on three counts of custodial interference.
Decker, who is described as 5 feet, 8 inches tall with black hair and brown eyes, was last seen wearing a light shirt and dark shorts, according to police. Decker's father is flying in to speak with detectives, officials said.
Officials said anyone who has any information on Decker or knows of his whereabouts should call 911 immediately. Another press conference regarding the search for Decker will be held on Wednesday evening, officials said.