"DEC. 14, 2012 Adam Lanza, 20, shot and killed his mother in their home, then killed 26 people, mostly children, at Sandy Hook Elementary School in Newtown, Conn., using a Bushmaster XM-15 rifle and a .22-caliber Savage Mark II rifle. 2009 Mr. Lanza graduated from high school. Some classmates said he had been bullied in high school. He struggled with a developmental disorder and was described as acutely shy, not known to have close friends. AFTER HIGH SCHOOL He was “completely untreated in the years before the shooting” for psychiatric and physical ailments like anxiety and obsessive-compulsive disorder, a state report found. BEFORE THE SHOOTING His mother, Nancy Lanza, a gun enthusiast, legally obtained and registered a large collection of weapons and would often take her sons to shooting ranges. DEC. 14, 2012 Mr. Lanza used his mother’s guns to kill her and 26 others."