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 least six 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 in her kindergarten classroom.
Police were investigating another body found in the family's Sandy Hook home. The identity of that victim had not been released.
Adam Lanza had another brother, 24-year-old Ryan, of Hoboken, N.J. He was mistakenly reported to be the killer.
Police say that Lanza drove to Sandy Hook Elementary School in Newtown in his mother's car.
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. Chang reported that Lanza might have been mistaken for a member of the clergy and allowed into the school.
A law enforcement official who said Adam Lanza had a possible personality disorder 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 were still searching his computers and phone records. Ryan Lanza told law enforcement he had not been in touch with his brother since about 2010.
Police did not release any motive for the killings.