No, I think they would have mentioned it if he had killed Luke's mother as well. It is obviouse he is a orphan, so if Vader killed his mother there would be no reason for Obi-Wan and Luke not to have talked about it. Luke seemed to have closure over his mother's death, based on the fact he immediately jumped to asking just about his father's rather than his parent's death. My guess is that after her husband was killed, Luke's mother moved to live with her brother and his wife or her sister and her husband depending on whether it is Beru or Owen that is her blood relation. I guess Owen could be Luke's paternal aunt. At any rate, It would make sense that she moved in with the Lars so they could help her out during her diffucult time. I bet she died sometime when Luke would have been concious about it.

Hmm, I think they should call the second one Star Wars II: The Wrath of Vader! How fantastic of a name for a sci-fi film would that be!