Nima Momeni, 38, was taken into custody Thursday in the nearby city of Emeryville and charged with murder in the stabbing of Lee, 43, on a downtown street in San Francisco in the early morning of April 4, police said. A LinkedIn profile for Momeni lists him as an IT consultant and entrepreneur.

San Francisco Police Chief Bill Scott said at a news conference that the two men knew each other, but declined to provide details on the alleged motive behind the fatal attack or how they identified Momeni as the suspect.

Mission Local, an online news site in the city, reported that the attack followed an argument Lee and Momeni were having while driving in Momeni’s vehicle and that the knife used in the attack was recovered not far from the spot where officers initially responded to the incident. Mission Local didn’t cite the source of its information.

“I know that everyone has wanted answers since this tragedy happened,” San Francisco District Attorney Brooke Jenkins said at the press conference. She said Momeni is being held without bail and will be arraigned Friday.

Lee’s brother, Tim Oliver Lee, thanked police for “bringing this person to justice so quickly” in a social media post, as did San Francisco Supervisor Matt Dorsey, who represents the district where Lee was killed.

“I’m grateful to @SFPD’s Homicide Detail and all the officers from @SFPDSouthern and elsewhere for their tireless work to bring Bob Lee’s killer to justice and for their arrest of a suspect this morning,” he wrote.

Lee was the first chief technology officer of Square, the startup co-founded by Jack Dorsey, and now called Block Inc. While at the company, he created CashApp, a money transfer tool that lets users buy stocks and Bitcoin. Earlier in his career, he helped develop Android while working as a software engineer for Google.

Momeni owns a small IT firm called Expand IT Inc. On Thursday, as news reports circulated about his arrest, the firm’s LinkedIn page suddenly became unavailable and the company’s website went down. Earlier in the day, LinkedIn said that the firm had less than 10 employees.

His company’s website previously listed testimonials from customers and a phone number to call to request services. Phone calls to the number listed for Momeni’s IT company went to automated lines that directed callers to voicemail. State business registration records indicated his company was based in Emeryville.

Momeni lists the University of California, Berkeley on his LinkedIn profile. The university didn’t immediately respond to an inquiry as to whether Momeni attended or graduated from the school.

Momeni donated $250 to Donald Trump’s presidential campaigns in 2016 and 2020, according to OpenSecrets. In 2020, he also donated $250 to the Democratic Senatorial Campaign Committee.