(CNN) - The suspect in the Connecticut school shootings is Adam Lanza, 20, the son of a teacher at the school where the shootings occurred, a law enforcement official said Friday. A second law enforcement official says the boy's mother, Nancy Lanza, is presumed dead.
Adam Lanza's older brother, Ryan, 24, of Hoboken, N.J., is being questioned by police, said the first official. Earlier, a law enforcement official mistakenly transposed the brothers' first names.
Both officials spoke on the condition of anonymity because they were not authorized to speak on the record about the developing criminal investigation.
The first official said Adam Lanza is dead from a self-inflicted gunshot wound.
According to the second official, the suspect drove to the scene of the shootings in his mother's car. Three guns were found at the scene -- a Glock and a Sig Sauer, both pistols -- and a .223-caliber rifle. The rifle was recovered from the back of a car at the school. The two pistols were recovered from inside the school.
All the guns were purchased legally and registered to Lanza's mother, according to NBC News.
Lanza's father, Peter, lives about 40 miles away from Newtown in Stamford, where he works as a tax specialist for GE Energy Financial Services. Court records indicate the parents were divorced in September, 2009.
An official also said Lanza's girlfriend and another friend are missing in New Jersey.
Meanwhile, former Jersey Journal staff writer Brett Wilshe said he has spoken with Ryan Lanza of Hoboken, who told Wilshe the shooter may have had Ryan Lanza's identification.
Ryan Lanza has a Facebook page that posted updates Friday afternoon that read that "it wasn't me" and "I was at work."
READ | More details about the Newtown shooting | http:// bit.ly/ SWeGMA
CNN, NBC and the Associated Press contributed to this report.