SAN FRANCISCO (KRON) -- San Francisco Assistant District Attorney Omid Talai continued his cross-examination of Bob Lee murder suspect Nima Momeni on Thursday. Talai's questions focused on ripping apart Momeni's testimony from Wednesday's direct examination. Momeni accused Bob Lee of exploding with anger after Momeni made a "bad joke" about Lee spending time in strip clubs instead of with his family. Momeni told jurors that on April 4, 2023, Lee pulled out a knife, and the defendant re-directed the knife back to Lee. "I was afraid for my life. I had to control the knife. It happened so fast," Momeni testified. Lee was stabbed three times, including once through the heart, investigators said. Momeni told the jury that he had no idea Lee was injured until he learned about the tech mogul's death a day later. San Mateo Co. sheriff promotes chief of staff after report alleges intimate relationship "He was fine when he left. He walked away on his phone," Momeni testified.  During his second day on the stand, Momeni continued to claim that Lee tried to kill him because of the "bad joke."  Nima Momeni in court (Sketch: Vicki Behringer) Talai fired off dozens of questions to re-establish a motive behind the murder. In opening statements, prosecutors said Momeni was angry over Lee's relationship with his sister, Khazar Momeni. Khazar testified that Lee introduced her to his drug dealer on April 3, 2023, and the drug dealer sexually assaulted her using a "date rape drug." Khazar said she woke up face-down on the drug dealer's bed wearing only a bikini. Lee was slain the next day.  On Thursday, Talai's questions on cross-examination attempted to illustrate to jurors that Momeni was angry with Lee because his drug dealer sexually assaulted his sister, Khazar.  Talai asked, "Is it fair to say, if someone thinks their little sister was date raped with drugs, that would make them very, very, very angry?" Momeni answered, "It depends on the situation. In this case, she had asked for the drugs, she knew what she was taking. There is clear communication about how I handled that suspicion." "On April 4, you texted your sister, 'Close your day.' What did you mean by that?" Talai asked. Momeni replied, "I meant, shut down your schedule. I was trying to get her to calm down and not party anymore. No more parties for you." "The phone call to Bob around 9 p.m., you called Bob because you wanted answers. And your sister was in the background," Talai replied. "Yes," Momeni said. "Because I wanted to talk to him about Jeremy (the drug dealer) and Bo. (My sister) never complained about Bob, she was talking about Bo (Mohazzabi, friend of Bob Lee) and Jeremy." "Bob answered your questions politely?" Talia asked. Momeni said that he had. The prosecutor and the accused killer began sparring back and forth in the courtroom as Momeni pushed back on questions and pointed his finger at Talai. The judge reminded Momeni that the prosecutor is allowed to ask questions seeking facts.  Nima Momeni in court (Sketch: Vicki Behringer) Talai asked, "You barely knew (Bob Lee). You met him over Facetime a long time ago. Then you had that phone call with him at 9 p.m. on April 3. You saw him at your sister's place on April 4 at the Millenium (Tower). In those limited interactions, did he seem like a positive, confident, normal guy?"  Momeni answered, "Yes, he had a big character."  "So, he lost his mind and wanted to kill you over a bad joke?" Talai responded. Momeni said, "He got angry at me, he got aggressive, he pulled a knife out, and I defended myself. (Bob Lee) said, 'You think I'm a bad f**king dad? I'm going to f**k you up.' He was angry, circling me."  "Are you aware that he has a wonderful relationship with his family? He has a good relationship with his family," Talai responded. "I didn't even know if he had a family," Momeni replied.  "Did you know he was in town and did spend time with his daughter for her play?" Talai asked.  "He did not mention anything about family," Momeni replied.  "How exactly did you make this deadly joke?" Talai asked. "I told you that already," Momeni replied.  "Tell it to me right now," the attorney countered.  Momeni responded, "I said, 'If I knew this was my last night in town, I'd spend it with my family instead of f**king around in strip clubs.' I'm not sure why he was so sensitive about the subject. It didn't make sense, it still doesn't." The prosecutor asked the defendant about his text messages with the drug dealer after Khazar said she was sexually assaulted by him.  "In a text message to Jeremey, just 20 minutes later, you threatened him," Talai said. Momeni refused to answer the question until the prosecutor displayed the full text message thread to the courtroom.   Talai fired back, "I will show the text. When you cut me off when I ask questions, is that what you did to Bob on the phone?"  Momeni answered, "You are accusing me of something I didn't do. You're in my face trying to be argumentative." Talai quipped, "So, it's just me?" Momeni answered, "Yes." Stick with KRON4 for the latest developments in the Bob Lee murder trial.