(S (S (S (NP (BASENP (DT The) (NN cause)) (PP (IN of) (BASENP (NN death)))) (VP (VP (VP (VBZ is) (RB not)) (VP (ADVP (RB yet)) (VBN known))) (CC and) (VP (VBZ is) (VP (VBG being) (VP (VBN treated) (PP (IN as) (QT (DQL ``) (ADJP (JJ unexplained)) (DQR '')))))))) (COMMA ,) (PP (VBG according) (PP (TO to) (BASENP (DT the) (NN metropolitan) (NN police))))) (PERIOD .))