Prosecution begins closing argument in trial over stabbing death of Cash App founder Bob Lee

SAN FRANCISCO -- Closing arguments began on Monday in the trial of a tech consultant in the 2023 stabbing death of Cash App founder Bob Lee in San Francisco, an event that shocked the broader tech community whose members mourned the loss of an entrepreneur they called charismatic and kind.

San Francisco prosecutors say Nima Momeni stabbed Lee three times after hearing that Lee's drug dealer friend plied Momeni's younger sister with GHB and other drugs and sexually assaulted her.

“One person called 911 pleading for help, saying somebody stabbed me,” said Dane Reinstedt, assistant district attorney, adding that the other person never called police or told anyone what happened that night until the trial.

Defense attorneys say Lee, 43, was on a multi-day drug bender of cocaine and ketamine that made him agitated and violent, and that he attacked the defendant with a knife. They said Momeni was forced to use his Krav Maga martial arts skills in the early morning hours of April 4, 2023, after making a “ bad joke " that upset Lee — and did not realize he had stabbed him.

Momeni faces 26 years to life if convicted of murder. He has pleaded not guilty.

Reinstedt on Monday mocked Momeni's defense as he walked jurors through evidence from the trial that began Oct. 14.

He said Momeni was furious with Lee for introducing Khazar Momeni, with whom he was friends, to a drug dealer who gave her GHB, known as a date-rape drug, hours before the stabbing. They say Momeni grilled Lee earlier in the evening about what happened to his sister at the drug dealer’s apartment and sent text messages saying that the two men were creeps and sexual predators.

Then, Momeni met up with Lee at his sister's condo, took a paring knife from her kitchen set, drove Lee to a secluded area by the Bay Bridge and stabbed him three times, Reinstedt said.

“That protectiveness of the defendant’s little sister is what led to all of this," he said.

The puncture wounds were clean, clear and deep, and not the result of any kind of self-defense tussle, he said. 99% of the DNA on the handle of the knife belonged to Momeni, the prosecutor said.

The trial has been emotionally taxing for family members of both men. Mahnaz Tayarani, mother of the defendant, has sat on one side of the court room while Lee's father, brother and ex-wife sat on the other. The prosecution started its closing argument with a 911 call in which Lee could be heard asking repeatedly for help.

Surveillance video of Bob goofing around on his final night and autopsy photos of his wounds have been difficult to view, said Lee's brother, Timothy Oliver Lee. He dismissed Momeni's explanation of events as a fabrication.

"Even if he was under the influence, he was still Bob. He was never aggressive. He was always a teddy bear and always a great guy,” he said.

Surveillance video shows the two men leaving the posh condo of Khazar Momeni around 2 a.m. and getting into Momeni's BMW. Other surveillance then shows them getting out of the car in an isolated section of the city by the Bay Bridge.

Momeni testified 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 his last night visiting the city with family instead of trying to find a strip club to keep the party going.

That's when Lee suddenly pulled a knife, Momeni said. He said Lee later walked away, showing no signs he was injured.

“I was scared for my life," Momeni said in earlier testimony that was at times rambling and contentious. "I had to defend myself.”

Lee was found staggering on a deserted downtown San Francisco street at 2:30 a.m., dripping a trail of blood and calling for help. He later died at a hospital.

Jurors were allowed to ask questions and, through San Francisco Superior Court Judge Alexandra Gordon, asked why Momeni did not call police, either after Lee's knife attack or after Momeni realized Lee had been stabbed to death.

A knife recovered from the area where Lee was stabbed showed Momeni’s DNA on the handle, but the defense said the handle should have been tested for Lee’s fingerprints.

Lee’s death stunned the tech community as fellow executives and engineers penned tributes to his generosity and brilliance. He was chief product officer of cryptocurrency platform MobileCoin when he died.