(S (S (BASENP (NNS Officials)) (VP (VBD commented) (SBAR (IN that) (S (BASENP (DT some) (NNS relatives)) (VP (VBD had) (VP (VBN expressed) (NP (BASENP (PRPD their) (NN frustration)) (PP (IN over) (NP (BASENP (DT the) (JJ legal) (NNS challenges)) (VP (VBN involved) (PP (IN in) (BASENP (DT the) (NN prosecution) (NN effort))))))))))))) (PERIOD .))