carried out by men of marginal intelligence , 
(ROOT (S (VP (VBN carried) (PRT (RP out)) (PP (IN by) (NP (NP (NNS men)) (PP (IN of) (NP (JJ marginal) (NN intelligence)))))) (, ,)))
(ROOT (S (VP (VBN ) (PRT (RP )) (PP (IN ) (NP (NP (NNS )) (PP (IN ) (NP (JJ ) (NN )))))) (, )))