NEWTOWN, Conn. - UPDATE
Authorities now say the Connecticut school shooting suspect is 20-year-old Adam Lanza. Earlier, they had identified the shooter as Lanza's older brother, Ryan, who is only being questioned.
The suspected gunman was first identified as Ryan Lanza by multiple news sources, including ABC News, CNN and The Associated Press.
The gunman's identity has yet to be officially confirmed by Connecticut and law enforcement officials who cite investigation procedures as the reason.
One law enforcement official says the boys' mother, Nancy Lanza, was affiliated with the school. ABC reports that she was found in the family home, shot to death.
Another murder that is believed to be related to the case was reported at a residence in New Jersey.
The official also said Ryan Lanza's girlfriend and another friend are missing in New Jersey.
An official said Adam Lanza died from a self-inflicted gunshot wound.