SAN FRANCISCO (KRON) -- Jurors returned to the San Francisco courthouse Wednesday for their fifth day of deliberations but were unable to reach a verdict for the accused killer of tech mogul Bob Lee. From evidence and witnesses presented at a 2-month-long murder trial, jurors must decide: Did Nima Momeni stab Lee to death as a premeditated act of murderous revenge on April 4, 2023? Or, was the defendant telling the truth when he testified that he acted in self-defense? Twelve jurors have already deliberated for 29 hours since they first entered the room last week. Momeni, 40, is charged with first-degree murder. Prosecutors said he killed Lee as an act of revenge after Lee’s drug dealer sexually assaulted Momeni’s sister, Khazar. Momeni also suspected that Lee had an "inappropriate" relationship with her, according to trial evidence. Momeni said the Cash App founder attacked first because he made a "bad joke" and he re-directed the knife back at Lee. If jurors believe that he killed Lee in self-defense, they could find him not guilty of murder, and guilty of manslaughter. Bob Lee’s accused killer ‘arrogant’ on the stand, brother says Judge Alexandra Gordon's instructions for jurors state, "Your verdict on each count must be unanimous. This means that, to return a verdict, all of you must agree to it. You must reach your verdict without any consideration of punishment." Bob Lee and Nima Momeni (Photos via X / Getty Images) Once the jury agrees on a verdict, the foreperson will sign a verdict form and notify the bailiff. When the judge decides that the verdict is ready to be announced, Momeni's defense team, prosecutors, Lee's family, and Momeni will be quickly summoned to the courtroom. The judge's instructions state, "Each of you must decide the case for yourself, but only after you have discussed the evidence with the other jurors. Do not hesitate to change your mind if you become convinced that you are wrong. But do not change your mind just because other jurors disagree with you." Jurors are reviewing testimony from dozens of witnesses, as well as surveillance videos, text message exchanges, Lee's 911 call, autopsy reports, and DNA analysis. Khazar Momeni walks out of a San Francisco courtroom with her mother on Oct. 22, 2024. (KRON4 Photo) Lee spent his last three days alive partying with friends around San Francisco, including: Khazar; his alleged drug dealer, Jeremy Boivin; and a nightclub DJ, Bo Mohazzabi. Khazar and Mohazzabi testified on the stand. Boivin did not testify because the district attorney's office refused to grant him immunity from prosecution, court documents state. Momeni's lead defense attorney, Saam Zangeneh, told jurors, "Jeremy Boivin was the centerpiece. He was an instrumental witness. I can tell you defense attorneys cannot offer immunity." Lee, 43, was stabbed three times under the Bay Bridge. He called 911 begging for help before he died from a fatal stab wound through his heart, evidence at trial showed. Momeni, who was not injured, drove away from the crime scene in his white BMW and returned home to Emeryville, surveillance video revealed. Legal analyst Steven Clark said there are likely "two competing narratives" happening inside the deliberation room. "What the jury is likely doing, is going through the most serious charge first. And if they cannot find Mr. Momeni guilty of first-degree murder, they would then consider second-degree murder. The longer this goes on, the better it is for the defense. That means these jurors have divided into two factions and have competing positions on the case, which would be good news for the defense," Clark said. "It's a very complex jury process because they have so much to decide. This deliberation process could drag on," he added.