AP Source: 20-year-old Suspect Had Ties to School

The official said that a gun used in the attacks is a .223-caliber rifle. The official also said that New Jersey state police are searching a location in that state in connection with the shootings, said by an official in Connecticut to have left 27 dead, including 18 children.

The official in Washington spoke on the condition of anonymity because the source was not authorized to speak on the record about the developing criminal investigation.