We could be looking at one of the worst mass shootings in U.S. history, exceeded only by the Virginia Tech massacre in 2007.

The latest numbers are at least 27 people dead at an elementary school in Newtown, Conn., including 20 children.

Police say the body of the alleged shooter was found inside the elementary school. Unconfirmed reports say the shooter was Adam Lanza. (Police originally reported the shooter’s name to news outlets as Ryan Lanza.)

James Alan Fox, a criminology professor at Northeastern University, says the U.S. averages 20 mass shooting deaths per year.