Adam Lanza of Newtown, Connecticut was a child of the suburbs and a child of divorce who at age 20 still lived with his mother.
This morning he appears to have started his day by shooting his mother Nancy in the face, and then driving to nearby Sandy Hook Elementary School armed with at least two handguns and at least one semi-automatic rifle.
There, before turning his gun on himself, he shot and killed 20 children, who President Obama later described as between five and 10 years of age. Six adults were also killed at the school. Nancy Lanza was found dead in her home.
A relative told ABC News that Adam was "obviously not well."
Family friends in Newtown also described the young man as troubled and described Nancy as very rigid. "[Adam] was not connected with the other kids," said one friend.
State and federal authorities believe his mother may have once worked at the elementary school where Adam went on his deadly rampage, although she was not a teacher, according to relatives, perhaps a volunteer.
Nancy and her husband Peter, Adam's father, divorced in 2009. When they first filed for divorce in 2008, a judge ordered that they participate in a "parenting education program."
Peter Lanza, who drove to northern New Jersey to talk to police and the FBI, is a vice president at GE Capital and had been a partner at global accounting giant Ernst & Young.
Adam's older brother Ryan Lanza, 24, has worked at Ernst & Young for four years, apparently following in his father's footsteps and carving out a solid niche in the tax practice. He too was interviewed by the FBI. Neither he nor his father is under any suspicion.
"[Ryan] is a tax guy and he is clean as a whistle," a source familiar with his work said.
Police had initially identified Ryan as the killer. Ryan sent out a series of Facebook posts saying it wasn't him and that he was at work all day. Video records as well as card swipes at Ernst & Young verified his statement that he had been at the office.
Investigators are looking into whether Adam Lanza was carrying his older brother Ryan's identification at the time of the shooting, which may have caused the confusion. Neither Adam nor Ryan has any known criminal history.
With reporting by Pierre Thomas, Jim Avila, Santina Leuci, Aaron Katersky, Jason Ryan and Jay Shaylor
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