(S (S (BASENP (NNP Vandermaas)) (VP (VBD was) (VP (VP (VBN forced) (PP (TO to) (BASENP (DT the) (NN ground)))) (PP (IN by) (NP (BASENP (NN police) (NNS officers)) (COMMA ,) (SBAR (SBAR (WHNP (WP who)) (S (VP (VP (VBD ripped) (BASENP (DT the) (NN flag))) (PP (IN out) (PP (IN of) (BASENP (PRPD his) (NN hand))))))) (SBAR (WHADVP (WRB when)) (S (BASENP (PRP he)) (VP (VBD crossed) (BASENP (DT the) (NN police) (NN line))))))))))) (PERIOD .))