(S (S (BASENP (NNS Police)) (VP (VBP claim) (SBAR (IN that) (S (NP (BASENP (QP (DT some) (NN 600)) (NNS artifacts)) (PRN (COMMA ,) (SBAR (WHNP (WDT which)) (S (VP (VBD had) (VP (VBN been) (VP (ADVP (RB illegally)) (VBN excavated)))))) (COMMA ,))) (VP (VBD were) (VP (VBN found))))))) (PERIOD .))