(S (S (NP (BASENP (NNP Putin)) (CC and) (BASENP (JJ other) (JJ Russian) (NNS officials))) (VP (ADVP (RB strongly)) (VP (VBD denied) (NP (BASENP (DT any) (JJ prior) (NN knowledge)) (PP (IN of) (NP (BASENP (DT a) (NN plot)) (S (VP (TO to) (VP (VB kill) (BASENP (NNP Litvinenko))))))))))) (PERIOD .))