Tech Executive Was Left to ‘Slowly Die’ After Stabbing, Prosecutors Say

The man accused of killing the tech executive Bob Lee on a dark and secluded San Francisco street this month had argued with him earlier before stabbing him three times with a kitchen knife, prosecutors said in court documents released on Friday.

The suspect, Nima Momeni, 38, had asked in a phone call whether anything “inappropriate” had happened between Mr. Lee, 43, and Mr. Momeni’s younger sister, prosecutors said, describing details of the police investigation in a motion to hold Mr. Momeni without bail.

His lawyer, Paula Canny, said prosecutors were wrong to accuse Mr. Momeni, a tech consultant and entrepreneur, of murder because they lacked proof of premeditation or malice. “I wouldn’t describe this as a crime,” Ms. Canny said in a phone interview.

Prosecutors accused Mr. Momeni of stabbing Mr. Lee, who was instrumental in creating the mobile payment service Cash App, with the four-inch blade of a kitchen knife, including once through the heart. He then threw the bloodstained knife in a parking lot and raced off in his car, they said, leaving Mr. Lee, who was bleeding profusely, “to slowly die” on the deserted street.

During a brief court hearing on Friday morning, Mr. Momeni’s arraignment was put off until later this month. He was arrested and jailed on Thursday and has not entered a plea.

Asked about details in the court documents, Ms. Canny said that her client’s dispute with Mr. Lee that night had nothing to do with “romance,” instead suggesting that drugs might have been involved. When asked about that assertion during a news conference, San Francisco’s district attorney, Brooke Jenkins, declined to comment. Mr. Lee’s family could not be reached on Friday to respond.

But on Thursday, the family said Mr. Lee, who had recently relocated to Miami for work, visited San Francisco regularly because he had business there and because his two teenage daughters lived nearby with his ex-wife. Mr. Lee’s brother, Oliver Lee, 42, of Palo Alto, described his brother as a “humble,” nonjudgmental idealist.

The case is playing out against heated claims that law enforcement authorities have failed to adequately protect the city’s residents against crime. Although San Francisco’s murder rate is low compared with that of many other major U.S. cities, its downtown has been struggling to rebound from the coronavirus pandemic and dramatic layoffs in the tech industry.

The motion released by prosecutors on Friday details a series of interactions between Mr. Momeni, his younger sister, Khazar Momeni, 37, and Mr. Lee in the 11 hours before Mr. Lee’s death on April 4. Investigators’ retelling of events at apartments and a hotel room in the city is partly based on an account of a witness, who was not identified in the court papers but described himself as a close, longtime friend of Mr. Lee’s.

The witness said that he had met Ms. Momeni through Mr. Lee about three or four years ago and that he was unsure about the nature of their relationship.

According to the documents, the witness told authorities that Mr. Lee and Ms. Momeni were drinking together at an apartment in downtown San Francisco the afternoon before Mr. Lee died. The witness said that he and Mr. Lee then went to Mr. Lee’s hotel room, where Mr. Momeni questioned Mr. Lee over the phone about “whether his sister was doing drugs or anything inappropriate.”

The witness said that Mr. Lee reassured Mr. Momeni that “nothing inappropriate had happened,” the document states.

The witness said that he and Mr. Lee “continued to hang out” until after midnight, according to the prosecutors’ motion. Surveillance footage showed that Mr. Lee then went to Ms. Momeni’s residence at the Millennium Tower, a luxury apartment building, for roughly 80 minutes.

According to the charging documents, video shows Mr. Lee and Mr. Momeni leaving together in Mr. Momeni’s BMW, which he parked on the street where Mr. Lee was stabbed twice in the chest and once in the hip — an act that also appears to have been captured in grainier images from a more distant camera.

A week later, after investigators were able to unlock Mr. Lee’s phones, they discovered a text message from Ms. Momemi that prosecutors said showed she was concerned about Mr. Lee’s interaction with her brother. “Just wanted to make sure your doing ok Cause I know nima came wayyyyyy down hard on you,” it read, according to court documents.

On Thursday, Oliver Lee said the family had been informed that Bob Lee had been visiting a friend on the night of the murder. But, he said, no one in the family was well acquainted with the Momenis.

“I don’t think anybody knew them well except Bob,” he said. “We weren’t close to any of them.”