NEW YORK (MYFOXNY) -
The 20-year-old killer who went into a Connecticut elementary school had a troubled past and few friends. That was part of an emerging portrait of the man who killed 20 children and at seven adults, including his mother, before taking his own life.
Adam Lanza lived with his mother in and reportedly suffered from a personality disorder.
A law enforcement source told Fox 5 News that Lanza killed his mother, Nancy Lanza at her home.
Police say that Lanza drove to Sandy Hook Elementary School in Newtown in his mother's car.
"He was not voluntarily led into the school," police Lt. Paul Vance said. "He forced his way into the school."
Three guns were found at the scene - a Glock and a Sig Sauer, both pistols, inside the school, and a .223-caliber rifle in the back of a car.
Fox 5's Ti-Hau Chang cited a law enforcement source that Lanza came into the school wearing black clothing over a bullet proof vest.
A law enforcement official speaking on condition of anonymity said investigators believe Lanza attended the school several years ago but appeared to have no recent connection to it. It was not clear whether he held a job.
A spokesman for Western Connecticut State University says Lanza was an unusually young college student.
Paul Steinmetz, spokesman for the Danbury school, confirmed Monday that Lanza earned a 3.26 grade point average while a 16-year-old student. He dropped out of a German language class and withdrew from a computer science class, but earned an A in a computer class, A-minus in American history and B in macroeconomics, reported the Associated Press.
Steinmetz said Lanza was among a small group of 16-year-olds among the school's 5,000 undergraduates.
The Hartford Courant and The Wall Street Journal first reported Lanza's academic record at Western Connecticut State.
Steinmetz says Lanza took his last class in the summer of 2009 and did not return..
Adam Lanza had a brother, 24-year-old Ryan, of Hoboken, N.J. He was mistakenly reported to be the killer.
A law enforcement official said Ryan Lanza had been extremely cooperative, was not believed to have any involvement in the rampage and was not under arrest or in custody, but investigators searched his computers and phone records. Ryan Lanza told law enforcement he had not been in touch with his brother since about 2010.
His parents filed for divorce in 2008, according to court records. His father, Peter Lanza, lives in Stamford, Conn., and works as a tax director for GE.
Police did not release any motive for the killings.
The Associated Press contributed to this report.
This undated photo shows Adam Lanza posing for a group photo of the technology club which appeared in the Newtown High School yearbook. Authorities have identified Lanza as the gunman who killed his mother at their home and then opened fire Friday, Dec. 1
Adam Lanza in an undated photo circulated by law enforcement and provided by NBC News. (AP Photo/NBC News)
