An evidence technician from the Carver County Sheriff's Office shows… (Glen Stubbe )
Christian Philip Oberender killed his mother with a shotgun in 1995, when he was 14.
He was committed to a state hospital after being deemed mentally ill and a possible threat.
He's since been released, and in May, he got a legal gun permit in Minnesota and amassed an arsenal of 13 guns -- including an AK-47 and a Tommy gun. He began to post photographs of the guns on Facebook along with notes sympathizing with the gunmen at Columbine High School and Sandy Hook Elementary School, officials said.
Oberender, 32, was arrested Jan. 2 by Carver County sheriff's deputies on suspicion of being a felon in possession of firearms, with bail set at $100,000.
Police found a note in his bedroom, according to KARE-TV: "I feel the good part of me fade away. I don't know how long I can hold it in for. I think about killing all the time. ... The monster want out. I know what happens when he comes out. He only been out one time and someone die."
He was living in the home where he'd killed his mother.
A spokesman for the Carver County Sheriff's Office wasn't immediately available for comment.
A Minneapolis Star-Tribune investigation, citing records and interviews with officials, found that Oberender was able to buy his guns because of a "combination of deceit on his part, failures in the state court system, and haphazard data collection by state agencies."
The state's gun laws don't require fingerprints or a Social Security number for weapon purchaes, and Oberender flipped his name around for his gun-permit application and lied about his mental health history, the Star-Tribune reported.
His juvenile record -- for killing his mother -- had not been attached to his adult file, leaving a gap in his background, the paper reported.
"The system failed in this case," Carver County Sheriff Jim Olson told the Star-Tribune.
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