(S (S (S (BASENP (DT A) (NN suicide) (NN bomber)) (VP (VBZ has) (VP (VP (VBN killed) (NP (QP (ADVP (IN at) (JJS least)) (NN 24)) (NNS people))) (PP (IN near) (NP (BASENP (DT the) (JJ Pakistani) (NN army) (NNS headquarters)) (PP (IN in) (BASENP (NNP Rawalpindi)))))))) (SBAR (WHADVP (WRB when)) (S (S (BASENP (PRP he)) (VP (VBD detonated) (BASENP (NNS explosives)))) (SBAR (IN while) (S (VP (VP (VBG riding) (PP (IN on) (BASENP (DT a) (NN motorbike)))) (PP (IN outside) (NP (BASENP (DT a) (NN bank)) (COMMA ,) (ADVP (BASENP (QP (JJ several) (NN hundred)) (NNS metres)) (ADVP (RB away) (PP (IN from) (BASENP (NN army) (NNS headquarters))))))))))))) (PERIOD .))