GUY RAZ, HOST:
Law enforcement authorities are trying to paint a picture of the gunman, 20-year-old Adam Lanza, and what may have led him on that deadly rampage. NPR justice correspondent Carrie Johnson is here to talk about the investigation. Carrie, what more do we know about Adam Lanza at this point?
CARRIE JOHNSON, BYLINE: Guy, it's important to note Connecticut State Police still have not publicly identified the gunman, but from federal law enforcement sources who've talked to NPR, we have named him as Adam Lanza. He's a 20-year-old man. One law enforcement source described him to me as an ultimate recluse. He lived in Newtown with his mother. He died at the scene. The medical examiner has told us they have not done any autopsy yet on the gunman, and they expect to provide more details about the cause of death on Sunday.
It's also important to note that while people are struggling to understand his motivation, Guy, a federal source told me it does not appear as if he left any written note giving clues into his thinking. So they've been trying to talk with his older brother, Ryan, and his father to try to understand where Adam's head was at in advance of this crime. But they may have been out of touch with Adam, and he may have been estranged from them.
RAZ: What do we know about the weapons that he brought into that school?
JOHNSON: Some new information coming out this afternoon. He had two pistols at the scene inside the school - a Sig Sauer and a Glock. And he also had a .223-caliber Bushmaster rifle. Guy, that's a very lightweight semiautomatic rifle often used by the military, used also by the D.C. snipers several years back. The medical examiner, Wayne Carver, says all wounds that the victims suffered inside the school came from the rifle. That lightweight rifle is the primary weapon in this crime.
RAZ: And what about the secondary crime scene?
JOHNSON: So after the police responded at the school, they spanned out across the community and they found what they described as a secondary crime scene. It's a family residence in Newtown registered in the name of Nancy Lanza, Adam Lanza's mother. Lieutenant Paul Vance says he found some very good evidence there, although he has not described what that is. And he's also said that there's an adult female dead inside that house. NPR has confirmed it is Nancy Lanza, the gunman's mother.
RAZ: Carrie, where do state and federal investigators go from here?
JOHNSON: Right now, I'm hearing from federal law enforcement sources. They continue to believe that Adam Lanza acted alone. So for now, the threat he posed has been neutralized. That said, they're still actively pursuing leads. State police are in the lead, but they're being supported by the FBI; the Bureau of Alcohol, Tobacco and Firearms; federal prosecutors in Connecticut, and a whole alphabet soup of other federal agencies.
They're going to gun shops and trying to figure out whether the Lanza family tried to purchase other guns, whether they were members of shooting clubs in the area, whether any of these people, especially Adam Lanza, left some kind of electronic trail that would help people understand whether he had reached out or done any kind of email or online postings to social networking sites in advance of this crime to give a signal as to where he was going.
RAZ: That's NPR's justice correspondent Carrie Johnson. Carrie, thanks.
JOHNSON: Thank you. Transcript provided by NPR, Copyright NPR.