Bobby is furious when his grandmother Kathy Sullivan (Gillian Taylforth) returns to Walford and Ian and Jane decide to move her into Bobby's bedroom and move Bobby into Lucy's old bedroom. Jane catches Bobby trying to swap the rooms back in secret, and a physical scuffle ensues, which results in Bobby pushing Jane down the stairs. After she regains consciousness, Kathy arrives and Jane lies that she tripped and fell when helping Bobby move the last items from his bedroom. However, after hearing Kathy and Jane talking later, Bobby accidentally reveals to Kathy that he pushed Jane down the stairs, leaving Kathy shocked at his violent streak. Bobby starts a feud with Sharon's son, Dennis Rickman Jnr (Bleu Landau), which escalates when Bobby cruelly kills Dennis 's pet spider. Sharon tells Kathy that Bobby is evil and needs help, and Kathy tells Sharon that Bobby pushed Jane down the stairs, so Sharon decides she will report Bobby to the police about Lucy's killing but agrees to wait until after Christmas. Dennis tells Bobby that he killed Lucy, having overheard it from Sharon and Phil. Ian and Jane soon realise that Bobby knows the truth, and Ian does a deal with Phil to stop Sharon going to the police. Bobby then tells Ian what he knows and Ian confirms it is true. Jane then decides they should go to the police, as they are no longer protecting Bobby from the truth, but Ian comes up with another plan to help Bobby's anger issues and the family agree to send him to boarding school. He leaves late in January, after Ian bribes the school to take him early.