Accused killer Nima Momeni took the stand Wednesday morning to tell his version of events in the April 2023 killing of Bob Lee, claiming he turned the knife on Lee in self-defense.The defense appears to be taking the big gamble in the trial of Nima Momeni, putting the defendant on the witness stand and opening him up to potentially aggressive cross-examination by the prosecution.The Chronicle reported Wednesday, via San Francisco Superior Court officials, that Momeni was expected to be called testify in his own defense. This will be the first time that the public has heard anything directly from Momeni since his April 2023 arrest, nine days after Lee was found stabbed in the Rincon Hill neighborhood.The defense's theory of the case is that Lee, who had no reason to be angry toward Momeni, who he barely knew, took the kitchen knife out of Momeni's sister's apartment with the intent of attacking Momeni, and Momeni, who has martial arts training, turned the knife back on Lee and stabbed him three times, including once in the heart.The defense has contended that Lee acted in a sudden fit of aggression, brought on by cocaine and ketamine.Momeni will have to answer for how he and Lee ended up in the shadowy area underneath the Bay Bridge, shortly after the two had left Khazar Momeni's Millennium Tower condominium together — in what ostensibly seemed, at 2 am, to be Momeni offering a ride in his BMW back to Lee's hotel on the Embarcadero.Momeni will also have to answer for the multiple phone calls he made and texts he sent, suggesting he was increasingly upset about his sister possibly having been taken advantage of in an inebriated state earlier in the day.As NBC Bay Area reports, Momeni began his day of testimony Wednesday telling his childhood story, suffering abuse at the hands of his father in Iran, and how he, his mother, and sister were able to escape that abuse and move to the US when he was 15. He also testified about taking kung fu, and having self-defense training.Per KPIX, Momeni also answered questions from his attorneys about texts he exchanged and a phone call he had with Lee before they met up in person at Momeni's sister's home. Momeni contends that he was not upset with Lee.On Tuesday, as Mission Local reports, the defense called their forensics expert, John Marraccini, a former chief medical examiner in Florida. Marraccini testified that it was possible that Lee's wounds were the result of a self-defense maneuver by Momeni — in particular, the wound to Lee's hip, which could have been part of some deflection on Momeni's part.Marraccini also reportedly agreed, under cross examination by prosecutor Dane Reinstedt, that it was plausible that Lee was first stabbed in the chest twice, and then superficially stabbed in the hip as he moved away.The defense was arguably damaged Tuesday by the testimony of Aranza Villegas, the friend of Khazar Momeni who joined her and Jeremy Boivin in an apartment where Khazar Momeni suggests she was assaulted by Boivin. Villegas testified that Ms. Momeni had a tendency to "exaggerate," and that she did not witness anything untoward occur between Boivin and her — only something consensual. She further testified that Nima Momeni texted her extremely curious about what had gone on in the apartment.When asked by his lawyer Wednesday whether he was "upset" upon hearing about his sister getting so high and passing out at Boivin's apartment, he said, "yes," and "It was very unsettling," per the Chronicle. But he continued to say that Lee was not the person he was upset with. Contradictorally, Momeni also testified about Boivin coming to Khazar's condo to retrieve "some items" later that day when he was present, and said of Boivin, "he was super polite and apologetic about everything that had happened. It didn’t seem that he would be that type."Also, contradicting texts he sent to his sister that prosecutors will surely bring up in cross, suggesting he wanted to call the police and "sue" Boivin, Momeni denied believing that his sister was assaulted that day, saying, "It sounded like something my sister said, being emotional, trying to get attention," per the Standard.Momeni says that by 9 pm that evening, prior to the confrontation with Lee, he no longer believed that his sister was the victim of an assault.This is a developing story and will continue to be updated.Previously: Friend of Nima Momeni's Sister Contradicts Her Testimony About Sexual Assault