(CNN) -- The man authorities believe was responsible for the New Year's Day shooting death of a national park ranger in Washington state was a former soldier who owned many knives and guns despite an emotionally unstable, vindictive and anger-prone mind-set, the mother of his toddler daughter said in court documents.
Authorities on Monday found Benjamin Colton Barnes' body face down in a creek in Mount Rainier National Park, not far from where investigators believe he fatally shot park ranger Margaret Anderson.
Investigators say they believe Barnes shot the ranger after he blew through a checkpoint set up to check vehicles to make sure they had the proper winter gear necessary to travel the park.
Anderson and another ranger had set up a second roadblock to stop him when he jumped out of the car and opened fire. She was struck before she was able to get out of her vehicle, authorities said.
Anderson, 34, was the first Rainier park employee to be a homicide victim, and the devastated staff needed a few more days to recover before the park reopens Saturday, officials said Tuesday.
While investigators said they had little insight into Barnes' mind-set or motivations, the woman with whom he was in a custody dispute over their young daughter said in court documents filed last year that she was frightened to be in the same state with him.
"The weapons are harmful, and I don't know if he will try to use them against myself or my family," the woman wrote in a filing for a temporary restraining order filed with the Pierce County Superior Court on May 24.
She wrote in other documents reported on by CNN affiliate KIRO that Barnes might be suffering from post-traumatic stress disorder after a deployment to Iraq.
Barnes, 24, served as a radio and communications repair specialist with 2nd Squadron, 1st Cavalry Regiment, a unit of the 2nd Infantry Division located at Joint Base Lewis-McChord near Seattle, according to Army spokesman Troy Rolan.
He joined the Army in February 2007 and was deployed to Iraq from that year to shortly before his discharge in 2009, Rolan said. Details of his discharge were not immediately available, Rolan said, and Army policy prohibits release of information about a soldier's medical condition.
Despite photos of a muscular Barnes, shirtless, tattooed and brandishing two guns, Barnes wasn't a combat soldier. Instead, he was responsible for fixing radios and other communications equipment, Rolan said.
The weapons in the widely circulated photo didn't appear to be government-issued, Steven Dean, an assistant special agent in charge at the FBI's Seattle office, said Monday.
And he didn't appear to have any special wilderness or survival training, Dean said. Barnes was found face down near a creek in a T-shirt, jeans and one shoe.
Before the shooting at the national park, Barnes was wanted in connection with a shooting early Sunday in the Seattle suburb of Skyway that left four people wounded, two critically, according to the King County Sheriff's Office.
"There was kind of a show-and-tell with guns in the evening at a party," spokeswoman Sgt. Cindi West told CNN.
Shortly before 3 a.m. Sunday, one of the males at the party asked to see a gun belonging to another person, West said. When asked to give the gun back, the male refused.
"A fight ensued, and at one point at least two people pulled guns, and a shootout ensued. Witnesses said that Benjamin Barnes was one of the subjects that pulled a gun and fired," West said in a statement. Barnes left the scene with two others.
"It is unclear at this point who shot first and who was shot by whom," West said.
Authorities contacted Barnes' family after the incident in a bid to have him come in for questioning, according to authorities.
Meanwhile, a woman who said she had spurned Barnes' romantic advances said he visited her on Sunday morning, before Anderson's shooting, to wish her a happy new year, according to CNN affiliate KCPQ.
She told the station that she thought Barnes was a nice guy when they first met, but that he "seemed sketchy" after she got to know him better. That he turned to violence in his final days wasn't shocking to her, she told the station.
"It doesn't surprise me, honestly. He is a loose cannon. If he doesn't get his way or something makes him upset, he goes all the way out of control," she told the station.
The park remained closed Tuesday, as authorities continued to investigate the shooting and Barnes' death.
"We are still dealing with the loss," said Mount Rainier National Park spokesman Kevin Bacher. "Everybody is just devastated and exhausted by this, trying to get back on an even keel."
The last ranger fatalities at the park was in 1995 when two climbing rangers died during a rescue, officials said.
About 125 employees at Rainier are being offered counseling and other measures. "A very large number of our staff are very shook up by this event," said Bacher.
Anderson was one of about a dozen commissioned law enforcement officers at the park. They assist motorists, firefighters, campers and search-and-rescue personnel.
"Our rangers are trained to be prepared for anything," Bacher told CNN.
Condolences continued to pour in Tuesday to the Officer Down Memorial Page; 955 messages had been posted as of Tuesday evening in praise of Anderson's service and offering comfort to her family, including her husband Eric Anderson, who also worked as a ranger at the park, and their two children, 1 and 4.
"Everyone is talking about her," Patty Wrzesien, a waitress at Cruiser's Cafe, told CNN affiliate KING on Monday. "She was such a sweet, sweet lady."
Anderson had always liked the outdoors, and she liked helping people, her father, Paul Kritsch, told KING. And that is why she loved her job as a ranger, he said.
Her family is planning a memorial service, according to Bacher.
CNN's Patrick Oppmann contributed to this report.