(S (S (BASENP (PRP It)) (VP (VP (VBZ is) (VP (VBN believed))) (SBAR (IN that) (S (NP (QP (ADVP (IN at) (JJS least)) (NN two)) (NNS children)) (VP (VBD were) (VP (ADVP (RB also)) (VBN killed))))))) (PERIOD .))