's hard to believe these jokers are supposed to have pulled off four similar kidnappings before 
(ROOT (S (VP (VBZ 's) (ADJP (JJ hard)) (S (VP (TO to) (VP (VB believe) (SBAR (S (NP (DT these) (NNS jokers)) (VP (VBP are) (VP (VBN supposed) (S (VP (TO to) (VP (VB have) (VP (VBN pulled) (PRT (RP off)) (NP (CD four) (JJ similar) (NNS kidnappings)) (ADVP (RB before))))))))))))))))
(ROOT (S (VP (VBZ ) (ADJP (JJ )) (S (VP (TO ) (VP (VB ) (SBAR (S (NP (DT ) (NNS )) (VP (VBP ) (VP (VBN ) (S (VP (TO ) (VP (VB ) (VP (VBN ) (PRT (RP )) (NP (CD ) (JJ ) (NNS )) (ADVP (RB ))))))))))))))))