Bob Lee, the former chief technology officer of Square who helped launch Cash App, died after a stabbing attack in San Francisco last month.
CNN  — 

The man accused of fatally stabbing tech executive Bob Lee last month pleaded not guilty to murder in a San Francisco court Thursday.

Nima Momeni, 38, will be held in custody without bail, the judge said.

Assistant District Attorney Omid Talai argued Momeni presents a public safety risk and is a flight risk. He said the knife used in the killing was connected to Momeni. It was a knife of the same brand as found in his sister’s apartment, and Momeni’s DNA was found on the knife’s handle, Talai said.

Paula Canny, Momeni’s attorney, said the DNA testing on the knife “isn’t entirely accurate” and argued Momeni is not a flight risk, noting he had not fled in the nine days between the killing and his arrest.

“(He) is a loving son, hardworking, has never been convicted of a felony, has no criminal record or been convicted of a crime of violence,” she said. Momeni is not a citizen and would risk being deported to Iran, she added.

Canny said this was “never a case of ‘who done it,’ it was always a case about ‘what happened.’” Outside court Thursday, Canny offered a preview of her client’s defense.

“My defense is it was a combination of an accident and self-defense,” she said. “There was no premeditation or deliberation.”

Nima Momeni, charged with murder in the killing of Cash App founder Bob Lee, enters the courtroom at the Hall of Justice on Thursday, May 18, in San Francisco.

San Francisco District Attorney Brooke Jenkins defended the charge after the hearing. “We believe that this was an intentional killing,” she said.

The hearing comes more than a month after Lee, a 43-year-old who cofounded the mobile payment service provider Cash App, was stabbed to death in the Rincon Hill neighborhood in the predawn hours of April 4. An autopsy report shows he suffered knife wounds that pierced his heart and lung.

Authorities have said Lee and Momeni knew each other and were in a white BMW shortly before the stabbing at about 2 a.m. The prosecution’s case relies heavily on grainy security video of what they say was the fatal stabbing, but Canny has said, “I don’t think you can see anything” in the video.

A witness described as Lee’s close friend said Momeni and Lee had an earlier discussion about Momeni’s sister and “whether his sister was doing drugs or anything inappropriate,” according to court documents. Lee had told Momeni nothing inappropriate had happened, according to the documents.

Further, a message from Momeni’s sister to Lee afterward showed the sister checking in on Lee. “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,” she wrote, according to documents from the district attorney’s office.

The killing has rattled the San Francisco tech scene and spurred broader criticisms of crime in the city, including from Tesla and Twitter executive Elon Musk, who connected the killing to “repeat violent offenders” being released from custody. However, Jenkins criticized Musk’s statement as “reckless and irresponsible” and said his remarks “assumed incorrect circumstances” about the case.

Lee was the former chief technology officer of Square who helped launch Cash App. He later joined MobileCoin, a cryptocurrency and digital payments startup, in 2021 as its chief product officer.

Momeni has been the owner of an IT business, California Secretary of State records indicate. He has been held without bail since his arrest last month.

Prosecutors reliant on security video

Motion-to-detain documents and surveillance footage from the DA’s office last month laid out what authorities say preceded the stabbing.

The footage shows Momeni arriving at his sister’s apartment building in a white BMW around 8:30 p.m. on April 3, and later shows Lee entering the building around 12:39 a.m. on April 4.

A little after 2 a.m., security footage shows Lee and Momeni leaving the building and getting into Momeni’s BMW. Additional footage from the area shows the two driving in the car together.

Video then shows the BMW drive to a “dark and secluded area” on Main Street, just out of view for the video to see the interaction between the two men, per the document.

Eventually, the two subjects, who are unidentifiable by their faces but seem to be wearing the same clothing as earlier, appear back in frame. After about five minutes, the subject wearing a white-colored top, consistent with what Momeni appeared to be wearing, “suddenly move(s) toward the other subject,” the document says. The two subjects then separate.

The person in dark-colored clothing, who authorities believe to be Lee, walks northbound, while the person in the light-colored clothing walks south and stops along a fence, where a knife was ultimately recovered, the document says. The BMW then speeds away, the document states.

A kitchen knife was found near the scene, Jenkins has said.

The toxicology report shows Lee had cocaine, ketamine and alcohol in his system at the time of the stabbing, but the substances were not indicated as a factor in his death.

The alcohol was equivalent to the amount of a beer, and the ketamine could have been given as anesthesia in the hospital, said Dr. Kendall Von Crowns, the chief medical examiner in Tarrant County, Texas, who reviewed and analyzed the toxicology report for CNN.

Canny used the toxicology report to accuse Lee of unstated wrongdoing and said it would be a factor in Momeni’s defense.

CNN’s Cheri Mossburg, Carma Hassan, Holly Yan and Phil Gast contributed to this report.