(S (S (S (BASENP (JJ Ballistic) (NNS reports)) (VP (VBP confirm) (SBAR (IN that) (S (BASENP (DT the) (JJ same) (NN gun)) (VP (VBD was) (VP (VBN used) (PP (IN in) (NP (BASENP (DT both) (NNS instances)) (PP (IN of) (BASENP (DT the) (NN campus) (NNS shootings))))))))))) (CONJP (COMMA ,) (CC but)) (S (BASENP (NN police)) (VP (VP (MD could) (RB not)) (VP (VB confirm) (SBAR (IN if) (S (BASENP (DT the) (NN shooter)) (VP (VBD was) (BASENP (DT the) (NN same))))))))) (PERIOD .))