(S (S (BASENP (NNP UN) (NN peacekeeping) (NN chief) (NNP Alain) (NNP Le) (NNP Roy)) (VP (VBD said) (SBAR (S (S (S (BASENP (JJ many) (NNS people)) (VP (VBD were) (PP (IN in) (BASENP (DT the) (NNP UN) (NN building))))) (SBAR (WHADVP (WRB when)) (S (BASENP (PRP it)) (VP (VBD went) (PRT (RP down)))))) (CC and) (S (BASENP (PRP they)) (VP (VBP remain) (ADJP (JJ unaccounted) (IN for)))))))) (PERIOD .))