• Cash App founder Bob Lee was having an affair with his accused killer's sister, Khazar Momeni, sources told WSJ. 
  • Khazar's brother, Nima Momeni, is in jail on murder charges in the fatal stabbing of Lee last month. 
  • Sources said Lee and Khazar were both part of "The Lifestyle," an underground San Francisco party scene.

Cash App founder Bob Lee, who was stabbed to death last month, was having an affair with the sister of his alleged killer, Nima Momeni, according to a new report from the Wall Street Journal. 

Friends of Lee who spoke to the Journal said Lee and Khazar Momeni, the wife of a well-known San Francisco plastic surgeon, were part of the same underground party circle known as the "The Lifestyle" and were casually sleeping together. 

The nature of Lee and Khazar Momeni's relationship was not previously known, though court documents show that Nima — a 38-year-old tech consultant who had known Lee for a decade — confronted Lee about his sister prior to the stabbing.

Lee and Khazar had reportedly been drinking with a group of friends at a house party in San Francisco prior to the altercation, which took place when Nima came to pick Khazar up. According to court records, Nima asked Lee if Khazar "was doing drugs [or] anything inappropriate" and proceeded to argue with the Cash App founder. 

According to witnesses at the scene, Lee told Nima that his sister had not taken any drugs and "nothing inappropriate had happened." A toxicology report later showed the presence of drugs in Lee's system, including ketamine and cocaine.

Later that evening, Nima and Lee both arrived separately to Khazar's apartment, before leaving together at 2:04 a.m. in Nima's white BMW Z4. Prosecutors say Nima then drove Lee to a "dark and secluded" San Francisco street corner and stabbed him in a "planned and deliberate attack."

"Just wanted to make sure your doing ok Cause [I] know nima came wayyyyyy down hard on you," Khazar wrote to Lee in a text following the confrontation, according to court documents. "Thank you for being such a classy man handling it with class. Love you Selfish pricks."

Sources speaking to the Journal said both Lee and Khazar were part of "The Lifestyle," a scene within the San Francisco tech community that involves recreational drug use and casual sex. According to court documents, prosecutors said Khazar was married, "but the relationship had possibly been in jeopardy." 

Gift Kerat, a friend of Lee who said she spent a lot of time with him during the pandemic, told the Journal that Lee had several girlfriends during this period, but "was respectful of them." 

In a statement provided to the Journal, Khazan's attorneys Mary McNamara and Ed Swanson said "There are many rumors circulating around this case, many of them untrue."

"Ms. Momeni loves and supports her brother," the statement said. "What happened here is a tragedy, and Ms. Momeni is deeply saddened at the suffering of the Lee family as they deal with their terrible loss."

Lee's wife Krista, with whom he was separated, told the Journal that he was not a "party boy" and she had never heard the term "The Lifestyle." 

"He was kind and generous — he saw the good in everybody," Krista Lee said. 

Police arrested Nima on April 13 on murder charges for the fatal stabbing of Lee and is being held without bail until his arraignment. He plans to plead not guilty, according to his attorneys.