Tonight a murder mystery full of outrageous twists. When one woman took the stand to testify in court she found herself being questioned by her own stalker. The same man on trial for killing her... See More
Tonight a murder mystery full of outrageous twists. When one woman took the stand to testify in court she found herself being questioned by her own stalker. The same man on trial for killing her roommate and attacking her roommate's 5-year-old son. It's a strange tale that unfolded over 17 years and came to a dramatic head in court today. Steve osunsami brings us the latest. Reporter: He may be dressed the part of a lawyer in suit and tie and legal briefs but he's the accused murder and convicted stalker, representing himself as the law allows and questioning the alleged victims in court. In 17 years you have never told anyone -- yes, I have. When? A few days after you murdered carmen. Reporter: At times the exchange is painful. The woman he stalked for years so scare she asked for her face to be kept from cameras. The question is inappropriate. It's hard for me to answer your questions. After you stalked me. Reporter: Police suspected he broke into this lower level apartment, strangled carmen smith and stand her son 18 times. Miraculously he survived. Police leave it was revenge against her roommate another mother who lived upstairs and helped send him to jail for stalking her. He ended up serving ten years. If I had known it would have led to this. I would have done things. Reporter: It was just before halloween. After murdering carmen smith he waited all day for her son to walk through the sliding doors. I got home from school. My mom's car was in the driveway. I thought she was home, and I -- I went down stairs and she wasn't there. Reporter: Nicholas smith is now a 22-year-old man. And this was his mother's birthday when he would finally sit face-to-face with the man accused of murdering his mom. The person the room grabbed me and started stabbing me a bunch. I tried to yell and he covered my mouth and then kept stabbing me, and then I got up and fainted. Reporter: It took police years to arrest daker but investigators say thanks to new dna tests they were able to connect hairs found on carmen smith's body to ker. He was still obsessed with the roommate, telling jurors they were an on again off again couple. She wfurious -- if I would know this turned into murder. If I had known I would take notes. I spent my entire life trying to erase everything and you want me to remember it all in a matter of days worth of trial. Reporter: Before convicting her there were voice mails where she worried he was unstable. You frighten me and I don't appreciate it. Maybe you're scared -- that you know you know you're lying cause -- Reporter: For nicholas smith, this was the man he believes left him with so many physical and emotional scars? You're telling me in 1995 -- no, I was in the hospital and had gotten repeatedly by you, so I don't think that was a very good time to be asking a 5-year-old questions like that. This is either a revictimization of the victim or potentially a cathartic healing experience. Reporter: B.J. Bernstein is a lawyer closely following this trial. There is something powerful about a victim being able to stand up and say, you do it. What's really empowering for someone is to look that person to eye and know that they, in a safe place, to be able to say, you know, you killed my mother, you stabbed me. These things happened to me. Reporter: Court officials aren't taking any chances forcing him to keep his distance away from the alleged victims. Marking the spot on the floor. No matter how awful the crime. The accused can represent themselves as trial. Even though he's acting as his own lawyer he can still sit in the witness and testify on his own behalf. Amazing story.
This transcript has been automatically generated and may not be 100% accurate.