(S (S (BASENP (NNP NATO)) (VP (VP (VP (VBD called) (BASENP (DT the) (NNS deaths))) (QT (DQL ``) (ADJP (JJ regrettable)) (DQR ''))) (CC and) (VP (VBZ is) (S (VP (TO to) (VP (VP (VB carry) (PRT (RP out))) (BASENP (DT an) (NN investigation)))))))) (PERIOD .))