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

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

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鈥檚 case relies heavily on grainy security video of what they say was the fatal stabbing, and the district attorney鈥檚 office has indicated the stabbing may have been premeditated.

鈥淭his is a person who was in his vehicle with a kitchen knife,鈥 San Francisco District Attorney Brooke Jenkins said of the suspect earlier this month. 鈥淭hat鈥檚 not something most of us carry around at all times with us.鈥

However, an attorney for Momeni said 鈥淚 don鈥檛 think you can see anything鈥 in the security video and said she believes she has evidence to support his innocence.

A witness described as Lee鈥檚 close friend said Momeni and Lee had an earlier discussion about Momeni鈥檚 sister and 鈥渨hether his sister was doing drugs or anything inappropriate,鈥 according to court documents. Lee had told Momeni nothing inappropriate had happened, according to the document.

Further, a message from Momeni鈥檚 sister to Lee afterward showed the sister checking in on Lee. 鈥淛ust 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,鈥 she wrote, according to documents from the district attorney鈥檚 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 鈥渞epeat violent offenders鈥 being released from custody. However, Jenkins criticized Musk鈥檚 statement as 鈥渞eckless and irresponsible鈥 and said his remarks 鈥渁ssumed incorrect circumstances鈥 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鈥檚 office last month laid out what authorities say preceded the stabbing.

The footage shows Momeni arriving at his sister鈥檚 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鈥檚 BMW. Additional footage from the area shows the two driving in the car together.

Video then shows the BMW drive to a 鈥渄ark and secluded area鈥 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, 鈥渟uddenly move(s) toward the other subject,鈥 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 said in a news conference.

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.

Momeni鈥檚 attorney Paula Canny used the toxicology report to accuse Lee of unstated wrongdoing and said it would be a factor in Momeni鈥檚 defence.