(S (S (BASENP (NN Police)) (VP (ADVP (RB also)) (VP (VBD warned) (NP (BASENP (NNS civilians)) (SBAR (S (BASENP (DT the) (NN suspect)) (VP (MD may) (VP (VB have) (NP (BASENP (DT a) (NN gas) (NN pistol)) (CC and) (BASENP (DT a) (JJ semi-automatic) (NN rifle))))))))))) (PERIOD .))