Sandy Hook Memorial (Wikipedia Commons)

1. Newton School Shooting: December 14
28 people, including 20 children, were killed and 2 injured when Adam Lanza, 20, shot his mother dead at their home and then drove to Sandy Hook Elementary school forcing himself inside and shooting inside classrooms. The weapons Lanza used were two semiautomatic handguns, one assault rifle, and one assault shotgun, all stolen from his mother (so not obtained legally). His older brother told authorities Adam had a history of mental problems, but it is unclear whether he was mentally ill.

2. Accent Signage Systems shooting: September 27
Upon learning that he was being fired, Andrew Engeldinger, 36, went on a shooting rampage, killing a total of 7 people and injuring 1. The victims included the business owner, three fellow employees, and a UPS driver. He then killed himself. Engeldinger used one semiautomatic handgun which was obtained legally from an unknown location. Engeldinger had shown prior signs of possible mental illness. His family worried about his paranoia and delusions for at least two years prior.

3. Sikh temple shooting: August 5
U.S. Army Veteran Wade Michael Page, 40, killed 7 and injured 3 more when he opened fire at a Sikh temple before he died from a self-inflicted gunshot during a shootout with police. Page used a semiautomatic handgun obtained legally (there is no information on where he obtained the weapon). A psychiatric nurse who lived downstairs from Page said she believed that Page had a mental illness. His Army friends once broke into his apartment fearing he'd commit suicide.

4. Aurora theater shooting: July 20
During the opening night of "The Dark Night Rises," James Holmes, 24, opened fire in a movie theater killing 12 and injuring 58. He was arrester later outside of the theater. Holmes used two semiautomatic handguns, one assault riffle and a shotgun, all obtained legally from Gander Mountain stores in Thornton and Aurora, Coloradao; Bass Pro Shop in Denver, Colorado; and BulkAmmo.com. He was believed to have a history of mental illness and had seen at least three mental health professionals before dropping out of the university.

5. Seattle cafe shooting: May 20
6 people were killed and 1 injured when Ian Stawicki, 40, gunned down four patrons at a cafe, and another person during a carjacking nearby. He then shot himself as police closed in and died later that day in a Seattle hospital. Stawicki used two semiautomatic handguns obtained legally at Bull's Eye Shooter in Tacoma, Washington. His family said he was mentally ill.

6. Oikos University shooting: April 2
One L. Goh, 43, a former student of the university, opened fire in a nursing classroom, killing 7 and injuring 3 others. He fled the scene by car and was arrested nearby a few hours later. Goh used a semiautomatic handgun obtained legally at Bullseye in Castro Valley, California. He was described as being paranoid and mentally unstable by a former instructor at Oikos.

7. Su Jung Health Sauna shooting: February 22
Jeong Soo Paek, 59, returned to a Korean spa from which he'd been kicked out after an altercation. He gunned down two of his sisters and their husbands before committing suicide. His sister said his mental health had been deteriorating and that he had threatened to commit suicide. Paek used a semiautomatic handgun obtained legally at an unknown location.

The summary above displays details of one year of shootings and it is already evident that almost all of the weapons were obtained legally while the shooters had histories of mental illness. The larger picture is not much different. Since 1982, of the 143 guns possessed by killers, more than three quarters were obtained legally and majority of the killers were mentally troubled, according to a Mother Jones investigation.

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