>> less than a year before the murder. >> broke the back door down to get in. >> okay, what's your name? >> nicole simpson. >> okay. is he the sports caster or whatever? >> yeah. >> what is he doing, is he threatening you? >> he's going nuts. >> i was like, you can be pretty bad. >> 20 years later, juror number 4, david aldana, remembers that moment vividly. >> so that 911 tape made an impact? >> yeah, it did, because pounding on the door like that, i think you know his record by now. >> nicole's sister denise tells prosecutors she has seen simpson beat nicole, in person. >> he grabbed nicole, told her to get out of his house. wanted us all out of his house. picked her up, threw her against a wall. picked her up and threw her out of the house.