Police have arrested the former neighbor of the Upstate New York gunman who lured and then killed two firefighters on Christmas Eve. Dawn Nguyen, 24, faces a state charge of filing a falsified business record, along with a separate federal charge. The state charge is connected to the purchase of an AR-15 semiautomatic rifle and a 12-gauge shotgun, which were among the weapons gunman William Spengler had with him during the attack. Spengler killed himself after torching his home and a car to lure and then attack responding firefighters. Two died in the attack and three others were injured.