NEWTOWN, Conn. - A source identified the suspect in the Connecticut school shootings as Adam Lanza, and said he drove his mother's car to the school.
Family and friends remember Lanza as many things — intelligent, nerdy, goth, remote, thin.
Now the world will always remember him as a mass murderer.
ABC found a black and white group photo including Lanza in his high school yearbook, but his portrait space in the yearbook says "Camera Shy."
He might have suffered from a personality disorder, law enforcement officials said. The official did not elaborate, and it was unclear exactly what type of disorder Adam Lanza might have had.
So far, authorities have not spoken publicly of any possible motive. They found no note or manifesto, and Lanza had no criminal history. Witnesses said the shooter didn't utter a word.
According to ABC, 20-year-old Lanza shot his mother Nancy in the face before going to Sandy Hook Elementary School in Newtown armed with at least two handguns and a rifle.
State and federal authorities believe his mother may have once worked at the elementary school where Adam went on his deadly rampage, but not necessarily as a teacher. At least one parent said Adam Lanza's mother was a substitute teacher there. But her name did not appear on a staff list.
ABC is also quoting sources that said police are investigating reports that Lanza had an altercation at the school in the days before the shooting. CNN's Carol Cratty is also reporting that sources told her Lanza was involved in an altercation, but the sources didn't know who he argued with or the subject.
An official told the Associated Press that Adam Lanza's older brother, 24-year-old Ryan, of Hoboken, N.J., was questioned by police. An earlier report from a law enforcement official mistakenly transposed the brothers' first names leading to mistaken reports that Ryan was the shooter, the AP said.
Quoting two federal sources, ABC reported that identification belonging to Ryan Lanza was found at school, possibly leading or contributing to the confusion.
Ryan Lanza had been cooperative and was not under arrest or in custody, but investigators were still searching his computers and phone records. The brother told law enforcement he had not been in touch with Adam since about 2010.
The gunman died from a self-inflicted gunshot wound. His body was found inside a classroom, ABC News reported.
Adam Lanza and his mother lived in a well-to-do part of Newtown, a prosperous community of 27,000 people about 60 miles northeast of New York City.
Lanza's parents filed for divorce in 2008, according to court records. His father, Peter Lanza, lives in Stamford, Conn., according to public records, and he reportedly works as a tax director for General Electric.
Lanza's aunt Marsha Lanza, of Crystal Lake, Ill., said her nephew was raised by kind, nurturing parents who would not have hesitated to seek mental help for him if he needed it.
If her son had needed counseling, "Nancy wasn't one to deny reality," she said Friday. Marsha Lanza said her husband had seen Adam as recently as June and recalled nothing out of the ordinary.
Neighbors told ABC's Jim Avila that Nancy Lanza, was a "dignified woman" who was often strict with her children. The neighbor said that Nancy Lanza told friends that her younger son, Adam, was a troubled child with a learning disability who would often rebel against her strict teachings.
Adam Lanza attended Newtown High School, and news clippings from recent years show him on the honor roll. Joshua Milas, a classmate who was in the technology club with Lanza, said that he was generally a happy person but that he hadn't seen him in a few years.
"We would hang out, and he was a good kid. He was smart," said Milas, who graduated in 2009. "He was probably one of the smartest kids I know. He was probably a genius."
The tech club held "LAN parties" -- short for local area network -- in which students would gather at a member's home, hook up their computers into a small network and play games. Gloria Milas, Joshua's mother, said Adam Lanza's mother hosted one of the parties.
She recalled a school meeting in 2008 organized by the gunman's mother to try to save the job of the club's adviser. At the meeting, Milas said, Adam Lanza's brother Ryan said a few words in support of the adviser, who he said had taken his brother under his wing.
"My brother has always been a nerd," Ryan Lanza said then, according to Milas. "He still wears a pocket protector."
Catherine Urso, who attended a vigil in Newtown, Conn., said her college-age son knew the killer and remembered him for his alternative style.
"He just said he was very thin, very remote and was one of the goths," referring to a style of dress noted for a heavily black wardrobe.
Another former classmate, however, tweeted that Adam Lanza had been "weird" for a long time.
"As horrible as this was, I can't say I am surprised," Timothy Dalton wrote.
An official who spoke on condition of anonymity said it was not clear that Adam Lanza had a job, and there was no indication of law enforcement interviews or search warrants at a place of business.