(S (S (S (BASENP (PRP They)) (VP (VBD were) (VP (VBN thought) (S (VP (TO to) (VP (VB have) (VP (VBN been) (VP (VP (VBG heading) (ADVP (RB home))) (PP (IN for) (NP (BASENP (DT a) (NN holiday)) (VP (VBG marking) (NP (BASENP (DT the) (NN birthday)) (PP (IN of) (BASENP (DT the) (NN prophet) (NNP Muhammad))))))))))))))) (SBAR (WHADVP (WRB when)) (S (VP (VBN abducted) (PP (IN by) (BASENP (NNS insurgents))))))) (PERIOD .))