(Via Chicago Tribune)

Twenty-seven people were killed, including 18 children, the Associated Press reported, citing an official. The official spoke on condition of anonymity because the investigation was still under way.

The shooting appeared to be the nation's second-deadliest school shooting, exceeded only by the Virginia Tech massacre in 2007.

Sandy Hook Elementary School teaches children from kindergarten through fourth grade, roughly ages 5 to 10.

The gunman is said to be a 24 year old man and thought to have a relationship with someone at the school. 

President Obama has been notified of this tragedy. 

SOURCE