SAN FRANCISCO — Tech consultant Nima Momeni pleaded not guilty Thursday to a murder charge in the stabbing death of Cash App founder Bob Lee on the streets of San Francisco.

San Francisco Superior Court Judge Victor Hwang ordered Momeni, 38, kept in jail without bail, saying he posed a public safety risk if released. Momeni, who appeared in an orange sweatshirt and pants, did not speak, and his attorney Paula Canny entered the plea on his behalf.

Nima Momeni at an appearance at the Hall of Justice in San Francisco on April 25. Momeni has pleads not guilty to a murder charge in the death of tech entrepreneur Bob Lee. Jeff Chiu/Associated Press

The case has drawn national attention, partly given Lee’s status in the tech world. Lee was found with three stab wounds, including one to the heart, shortly after 2:30 a.m. April 4 and was taken to a hospital where he later died. He was found in the Rincon Hill neighborhood in downtown San Francisco, which has tech offices and condominiums but little activity in the early morning hours.

Lee, 43, created Cash App, a mobile payment service, and was the chief product officer of the cryptocurrency MobileCoin. He was mourned as a loving father of two who made friends wherever he went.

Prosecutors have not provided a motive but say Momeni stabbed Lee after a dispute related to Momeni’s sister, who appeared in court Thursday alongside their mother.

Assistant District Attorney Omid Talai argued Thursday to detain Momeni without bail, saying that the defendant drove Lee to a secluded spot and used a knife that was part of a unique kitchen set belonging to his sister. Police recovered a knife with a 4-inch (10-centimeter) blade at the scene.

Talai said that analysis showed Momeni’s DNA on the handle of the knife and Lee’s DNA on the bloody blade and no evidence that Lee had touched the handle, contradicting Canny’s claim of self-defense for her client.

But Canny said that Momeni did not drive Lee to a secluded spot with the aim of killing him. Instead, she said, Lee directed him to pull over after calling an Uber because the two had argued. The last time Momeni saw Lee, Canny said, Lee was standing upright and walking away.

“People can have a fight and not know that somebody’s been mortally wounded,” she said in court, later adding, “Every one of us, including my client, is heartbroken that Bob Lee died.”

Canny said Momeni has strong ties to the community and needs to stay and fight the charges or else face deportation to Iran, which would separate him from the two people he loves most, his mother and sister. Momeni is not a U.S. citizen.

Outside the courtroom, Canny described the encounter as “a cross between self-defense and accident. There was no premeditation deliberation.”

San Francisco’s District Attorney Brooke Jenkins rejected that idea in speaking to reporters after the arraignment. “We believe that we have the murderer of Mr. Lee, and that’s Mr. Momeni,” she said.

Nima Momeni was 14 when his mother took the children to the U.S., fleeing Iran and a husband who had inflicted years of abuse and violence on the family, his mother wrote in a letter submitted to the court in support of her son’s pre-trial release.

She said her son was generous and kind, pitching in financially when she enrolled in college to become a dental hygienist. He taught himself about computer technology.

Momeni was arrested last month at his home in Emeryville, which is across the bay from San Francisco.

An unnamed friend of Lee told homicide investigators they had been hanging out and drinking with Momeni’s sister the day before the stabbing, prosecutors said in a motion to detain Momeni without bail.

The friend said Momeni later questioned Lee about whether his sister was doing drugs or otherwise engaging in inappropriate behavior and Lee said she had not.

The friend and Lee later parted ways, and surveillance video showed Lee entering the posh Millennium Tower downtown, where Momeni’s sister Khazar lives with her husband, prominent San Francisco plastic surgeon Dino Elyassnia. Video footage then showed Lee and Momeni leaving the building together shortly after 2 a.m. and driving off in Momeni’s car.

Momeni faces 26 years to life if convicted.