(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 Calvary 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
When will the National Park reopen? Who is the alleged killer? Who was killed on Sunday? Who was the suspect? Was anyone else, hurt, or killed? What national park will reopen Saturday?
Saturday, Benjamin Colton Barnes' Benjamin Colton Barnes' former soldier four people wounded, two critically, Mount Rainier
question: When will the National Park reopen?, answer: Saturday, | question: Who is the alleged killer?, answer: Benjamin Colton Barnes' | question: Who was killed on Sunday?, answer: Benjamin Colton Barnes' | question: Who was the suspect?, answer: former soldier | question: Was anyone else, hurt, or killed?, answer: four people wounded, two critically, | question: What national park will reopen Saturday?, answer: Mount Rainier