When Cash App founder Bob Lee was stabbed to death on a San Francisco street nearly two years ago, it was initially assumed to be a robbery gone wrong and reignited an already growing fury over increased violence in the city.
But the assailant wanted nothing to do with Lee’s money, leaving behind the tech titan’s watch and wallet after stabbing him to death. Instead, as the district attorney’s office alleged, it was a murder of one tech professional by another, motivated by passion.
San Francisco Police Sergeant Brent Dittmer, who was the lead detective on the case, says he knew this early on.
“There was a lot of talk that this was random homeless violence in San Francisco – could that have happened? Maybe. But it very quickly appeared that was not the case,” Dittmer tells NBC Dateline’s Josh Mankiewicz, in a clip shared with The Independent. The detective pointed out that Lee had still had his watch and wallet when he was found, in the episode “Under the Bay Bridge” airing Friday evening.
Theories circulated online about a possible mugging, but even though Dittmer and his team believed it was something more, they chose to not to publicly dispute the theories.
“If that’s the story people are gonna run with, that is an advantage for us because the people who are responsible, we don’t want to know what we know.” he said “Let everybody think that this is whatever’s on Twitter at that time. We’ll work on what actually happened.”
The two-hour episode on Friday features exclusive interviews with Lee’s family and friends, as well as colleagues from the tech industry, dramatic surveillance video footage an in-depth look at the timeline leading up to his death, and the investigation that led to an arrest and conviction.
Lee’s former wife, Krista, also speaks to Dateline, revealing the emotional aftermath his family has endured as she insists he would have never have put himself in such a dangerous situation – which made his murder even more puzzling.
“The main people were saying that ‘he must have gotten mugged,’” she said about Lee who was allegedly walking back to his hotel late that night when the attack happened.
Krista said she never believed the robbery theory because Lee never walked anywhere.
“He would’ve Ubered. Especially at that time,” she said. “And had Bob been approached by someone that was trying to mug him, he would’ve given him, them, the shirt off his back, his wallet, his keys, his clothes. He would’ve said, ‘Hey, man, let me buy you a meal. Please don’t hurt me.’”
The 43-year-old beloved tech mogul was found staggering on a deserted downtown street, dripping a trail of blood and calling for help after being stabbed in the early hours of April 4, 2023. He was rushed to a hospital but died of his injuries.
Lee’s violent death sent shock waves through the tech world and drew national attention. A well-known figure in the tech community, yet there was no clear reason why someone would want to harm him.
At one point, his death inflamed debate over public safety in San Francisco as X owner Elon Musk took to the social media site to post that “violent crime in SF is horrific and even if attackers are caught, they are often released immediately.”
But later that month, when Nima Momeni, 40, a Bay Area IT consultant, was arrested and charged in Lee’s murder, the motive of the killing began to shift.
Prosecutors argued that Momeni intended to fatally stab Lee over an argument about his sister, whom Lee knew, and her reported drug use. Momeni said that Lee attacked him with a knife and that he defended himself and Lee was stabbed.
In December 2024, after seven days of deliberations, the jury found Momeni guilty of second-degree murder for killing Lee.
San Francisco District Attorney Brooke Jenkins said the verdict showed that the killing was a targeted crime and not an example of random lawlessness in the city.
The night of Bob’s murder
Lee, who had created mobile payment service Cash App and was the chief product officer of the cryptocurrency MobileCoin, had recently moved to Miami to be closer to his ex-wife and their two children, and had returned to the Bay Area for a visit.
The afternoon before the stabbing, Lee and Momeni’s sister Khazar Momeni had been doing drugs and drinking at the apartment of a drug dealer Lee knew, the Associated Press reported. Lee left before Nima Momeni went to pick up his sister, who told him she had been assaulted.
Prosecutors said Momeni was furious with Lee for introducing Khazar to the drug dealer who gave her GHB, known as a date-rape drug, hours before the stabbing.
A friend of Lee’s testified that Momeni then grilled Lee over the phone about what happened to his sister while at the drug dealer’s apartment. He sent text messages saying that the two men were creeps and sexual predators.
Momeni later hung out with Lee at his sister’s condo until she kicked them out, saying she needed to sleep.
Surveillance video shows the two men leaving Khazar Momeni’s posh condo around 2 a.m. and getting into Nima Momeni’s BMW. Other surveillance footage then shows them getting out of the car near the Bay Bridge, where the stabbing took place.
“That protectiveness of the defendant’s little sister is what led to all of this,” prosecutors said.
The trial
The trial for Momeni began on October 14, 2024, in San Francisco, more than a year after the murder.
In his first public statements about the events leading to Lee’s death, Momeni testified in his own defense, telling the court that he had joked to Lee that he might want to spend his final night in San Francisco with family rather than trying to find a strip club.
Momeni testified that he stopped his car after going over a pothole that caused Lee to spill the beer he was holding. Momeni said he then cracked a joke suggesting Lee should spend the last night of his visit with family instead of trying to find a strip club to keep the party going.
That’s when he says Lee snapped, yelled at him about questioning his parenting skills and pulled out the knife from his jacket pocket, and attacked.
“I was scared for my life,” Momeni said during trial, in testimony that was rambling and contentious.
He said Lee walked away from the encounter, and showed no evidence of being hurt. He didn’t realize Lee had died until the following day, he said.
“He’s a big famous guy,” he said on the stand. “I’m just an average joe, an immigrant.”
Momeni said he called an attorney when he learned of Lee’s death the following day.
“I feel awful to his family, to himself,” Momeni said on the stand. “He didn’t deserve it. I don’t think anyone deserved that.”
The prosecution mocked Momeni’s story, pointing out that he never called police to report Lee’s alleged attack or even after he learned Lee had died of stab wounds on the street where he had last seen him.
They also said the puncture wounds were clean, clear and deep, and not the result of any kind of self-defense tussle, he said. Just about all of the DNA — 99 percent — found on the handle of the knife belonged to Momeni, the prosecutor said.
Prosecutors also showed text messages Khazar Momeni sent her brother, asking where he had dropped off Lee — a question he sidestepped. She sent a text message to Lee checking on him because her brother came “down hard” on him and to thank him for “handling it with class.”
The jury found the tech consultant guilty of second-degree murder, rejecting the defendant’s claim that he had acted in self defense.
Momeni faces 16 years to life in prison. He has not yet been sentenced.
“We think justice was done here today,” the victim’s brother, Tim Oliver Lee, told reporters following the verdict. “What matters today is that we had a guilty verdict and Nima Momeni is going away for a very long time.”
