TODAY | February 13, 2013
>>> back now at 7:40 with nbc news special flashpoint guns in america coverage, and a case that raises troubling questions. how did a man who killed his mother and declared mentally ill and dangerous later find a way to get his hands on a shocking number of firearms? nbc's kevin tibbles has details on this story. good morning.
>> many am minnesota are asking how could this slip through the cracks, a young man who already killed his mother, now found with an arsenal along with something as equally disturbing.
>> this is a desert eagle , semi automatic.
>> reporter: stockpile of guns with immense fire power all seized in january from home of 32-year-old christian philip overender, minneapolis.
>> pretty concerned and i think everyone was quite scared, to be honest with you.
>> reporter: why were neighbors scared? back in 1995 , just then 14, he killed his mother, mary, in the same house with a gun.
>> it certainly rang a bell with me from that.
>> reporter: sheriff jim olsen was a young detective back then and when he heard that oberender posted guns on facebook, his memory told him to be concerned.
>> he should not have guns on facebook and he should -- he should just not have guns.
>> reporter: deemed mentally ill and dangerous by the courts and committed to a state psychiatric hospital for his mother's murder. he was released as an adult more thn than a decade ago. police discovered a 15-weapon arsenal that included assault rifles and ammunition. not only did you find the guns but a note he wrote to his dead mother.
>> a note that was chilling in its content.
>> reporter: oberender wrote i think about killing all the time time. the monster want out. it went on. the monster want to hurt people.
>> in the polarized world we're in right now, it seems as if you're either for, quote, unquote, gun control or for addressing the mental health issues. when the reality is that we need to reduce gun violence by doing both.
>> reporter: investigators are still trying to determine how oberender got the guns. it appears he obtained a legitimate firearms permit by transposing his first and middle names on the application. background check in this case wouldn't have worked anyway. the bureau of criminal apprehension had no record of his murdering his mother. that issue is also being investigated.
>> this certainly could have turned out a different way for us, for carver county , the state of minnesota .
>> and for america .
>> yeah, and for america .
>> reporter: the chief now shutters to think what might have happened, had his memory failed him. more than 80 people in minnesota previously committed by a judge have been found with weapons. oberender will be sentenced next month on these new charges. his attorney has not returned our calls.
>> you can see this and other stories on flashpoint.