Suspect in Cash App founder's killing was upset over his sister, D.A. says

Cards and bouquets of flowers lie at a tree's base

April 14, 2023 Updated 5:55 PM PT

Cash App founder Bob Lee was stabbed three times with a kitchen knife and left to “die slowly” on a San Francisco street, allegedly at the hands of a tech consultant angry over Lee’s relationship with his sister, San Francisco prosecutors said Friday.

Authorities released a detailed narrative of the events leading up to Lee’s slaying, which shocked San Francisco and the tech world. While some assumed Lee was a victim of street crime, prosecutors laid out a complex series of personal interactions that ended in his death.

Nima Momeni, a tech consultant and entrepreneur, was upset over whether anything “inappropriate” had happened with his sister and Lee, according to the documents prosecutors filed in San Francisco Superior Court asking a judge to keep him in custody without bail.

At 2:35 a.m. April 4, Lee, 43, was found bleeding from stab wounds near the San Francisco-Oakland Bay Bridge. He was taken to a hospital, where he died.

At 3:30 p.m. April 3, a close friend of Lee’s met him at an apartment on Mission Street, where Lee was with Momeni’s sister, the friend said in court documents. Lee, Momeni’s sister and another friend were drinking.

Lee told the friend they were leaving and invited Momeni’s sister to go with them. She declined, prosecutors said.

The friend went with Lee to his hotel room at 1 Hotel San Francisco, where the friend said Lee had a conversation with Momeni about his younger sister and how Momeni had picked her up from the Mission Street apartment. It’s unclear from court documents whether Lee and Momeni’s conversation took place in person, by phone or otherwise.

According to the friend, Momeni questioned Lee about whether his sister had done drugs or “anything inappropriate,” and Lee reassured him that nothing of the sort happened.

The friend, who was not identified in the court documents, had met Momeni’s sister three to four years ago and said that she was married but that “the relationship had possibly been in jeopardy,” according to prosecutors. The friend wasn’t sure whether Lee and Momeni’s sister had an intimate relationship.

Lee and his friend went to another apartment, where they hung out until Lee left at 12:30 a.m., according to the court documents. Lee’s friend called Momeni’s sister and asked whether Lee had gone to her apartment at Millennium Tower. She said that Lee went there “for a second” but that she fell asleep and didn’t know when he left.

The San Francisco Police Department retrieved surveillance video from Millennium Tower, showing a white BMW Z4 arriving at the property at 8:31 p.m. and Momeni leaving the car and entering the apartment. About 12:39 a.m., Lee arrived and also entered the apartment.

The video shows the pair leaving the apartment at 2:03 a.m., with Momeni wearing a light tan and white jacket and Lee wearing all black.

Surveillance footage then shows the BMW drive to a dark area on Main Street and park. Two subjects enter the frame, one wearing dark-colored clothing consistent with Lee’s clothes and one wearing a light-colored top consistent with Momeni’s jacket, according to prosecutors.

After standing for five minutes, the person in the light top moves suddenly toward the other person. The people then separate, and the person in the dark-colored clothing stumbles away injured. The person in the light-colored top walks south on the sidewalk and gets into the BMW, which speeds away.

Lee was stabbed once in the hip and twice in the chest, with one of the wounds directly penetrating his heart, according to an autopsy. He was left to “slowly die” after the attack, prosecutors said.

Police found a kitchen knife with a black handle that appeared to have blood on it in a parking lot near the sidewalk seen in the surveillance video of the stabbing, prosecutors said.

Investigators found Lee’s phone and unlocked it with a password from his family, prosecutors said. On the phone, investigators found a FaceTime call was made between “Nima Via Khazar” and Lee, according to court documents.

Prosecutors did not identify Momeni’s sister by name in the court documents, but sources familiar with the case said her name is Khazar Momeni.

Investigators also found a text message from Nima Momeni’s sister, who apologized to Lee for her brother’s behavior.

“Just wanted to make sure your doing ok Cause I know nima came wayyyyyy down hard on you And thank you for being such a classy man handling it with class Love you Selfish pricks,” the sister wrote.

Momeni, 38, was arrested Thursday and charged with murder and an enhancement for using a deadly or dangerous weapon, which carries an additional and consecutive year of imprisonment. If convicted, Momeni faces 26 years to life in prison.

According to a source familiar with the circumstances of the events leading up to the killing, Momeni and Lee were in the same friend group but didn’t know each other very well.

Lee was chief technology officer at the payments platform Square, which has since been renamed Block, when he founded the company’s mobile payment service Cash App in 2013. He lived in Mill Valley, Calif., after his mother died in 2019, then he moved to Miami in October, according to a Facebook post last week by his father, Rick Lee.

“Bobby worked harder than anyone and was the smartest person I have ever known,” Rick Lee wrote. “He will be missed by all those that knew him.”

At the time he was killed, Bob Lee was staying in San Francisco for a few days to spend time with friends after a MobileCoin leadership summit, said his friend Doug Dalton, who met Lee years ago when both were software engineers.

Lee and Momeni had friends in common but were not close, Dalton said.

Momeni owned a business called Expand IT, which he operated from the Emeryville, Calif., live-work building where he was arrested Thursday morning.

The company, which was founded in 2010, provided tech services for clients in healthcare, finance and other businesses, according to Momeni’s LinkedIn account.

Sam Singer, who works in an office next to Momeni’s and serves on the building’s board, said they met when Singer was moving into his space a month ago.

He called Momeni a “kind, professional gentleman” but noted an odd incident the night before Lee’s death, April 3, when a woman entered the building and screamed the name “Nima,” according to Singer as well as posts in the building’s private Facebook group.

Singer said the episode was so unnerving to residents that a complaint was filed about it.

Russell Haynes, owner of Coast Range Technologies in the San Francisco Bay Area, said Momeni was an IT consultant at his company in 2006. Momeni was a quiet, respectful worker who often went out in the field to troubleshoot problems at businesses, Haynes said.

“He was a young man, eager to learn IT. He wanted to run his own business,” Haynes said.

He was shocked to hear that Momeni was arrested on suspicion of murder.

“That’s not the Nima of my day,” Haynes said.

Momeni was charged in 2011 in Alameda County with driving with a suspended license and selling a switchblade knife. He pleaded no contest to the moving violation, the knife charge was dismissed, and he was sentenced to 10 days in county jail and three years of probation. He was also charged in 2004 with driving under the influence of alcohol, a misdemeanor. The charge was dismissed.

Neighbor Chris Donatiello said Momeni seemed friendly and welcoming, adding that nothing appeared amiss when he saw Momeni after Lee’s death.

“I saw him last week. Just outside in the parking lot,” Donatiello said. “I said, ‘Hey haven’t seen you in a while. How are you?’ and he said, ‘Better now that I’m seeing you.’”

Times staff writers Noah Goldberg and Salvador Hernandez contributed to this report.