(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.
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Mount Rainier National Park will reopen Saturday
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Ranger shooting suspect was vindictive, a former girlfriend alleges in court papers
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Another woman tells CNN affiliate KCPQ that Barnes was a "loose cannon"
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Ranger Margaret Anderson, killed Sunday, was the mother of two young girls
Despite photos of a muscular @placeholder, shirtless, tattooed and brandishing two guns, Barnes wasn't a combat soldier.