Update: The shooter originally identified as 24-year-old Ryan Lanza, is his brother, Adam Lanza, 20, who's mother was a kindergarten teacher at Sandy Hook Elementary. Adam was reportedly carrying his brother's driver's license, leading authorities to identify him as Ryan Lanza. According to NBC News, Adam rampaged through the school dressed in black and carrying two hand guns. He shot 20 children and 6 adults, one of which was his mother.

Another member of Ryan's family was shot and kllled at his home.

A second person is in custody in connection with the shooting.

Sandy Hook Elementary School in Newtown, CT is currently on lockdown after an unidentified male shooter entered the school and opened fire. Federal and state sources revealed to the Associated Press that 25 people were killed, including 18 elementary school children.

The shooting involved two shooters during the early hours of Friday morning prompting the town of Newtown to lock down all of its schools and draw SWAT teams to the school.

State Police confirm that one shooter is dead. A second gunman is apparently at large. Car-to-car searches are underway.

Story developing.

Source: ABC News