(S (S (S (BASENP (PRP It)) (VP (VBZ is) (VP (VBN believed) (SBAR (S (BASENP (PRP he)) (VP (VBZ has) (VP (VBN been) (VP (VBN killed) (PP (IN at) (NP (BASENP (DT a) (NN checkpoint)) (PP (IN in) (NP (BASENP (NNP Khar)) (COMMA ,) (NP (BASENP (DT a) (NN town)) (PP (IN in) (NP (BASENP (DT the) (JJ tribal) (NN district)) (PP (IN of) (BASENP (NNP Bajaur) (COMMA ,) (NNP Pakistan)))))))))))))))))) (COMMA ,) (SBAR (WHADVP (WRB when)) (S (BASENP (PRP he)) (VP (VP (VP (VBD opened) (BASENP (NN fire))) (PP (IN on) (BASENP (NN security) (NNS officials)))) (PP (IN from) (PP (IN inside) (BASENP (DT a) (NN car)))))))) (PERIOD .))