MobileCoin, Olga R. Rodriguez/AP
- 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.