(S (S (BASENP (DT The) (NNS boys)) (VP (VBP have) (NP (BASENP (DT a) (JJ 3-year-old) (NN sister)) (SBAR (WHNP (WP who)) (S (VP (VP (VP (VBD was) (RB not)) (ADVP (RB home))) (PP (IN at) (NP (BASENP (DT the) (NN time)) (PP (IN of) (BASENP (DT the) (NN stabbing))))))))))) (PERIOD .))