Cash App founder Bob Lee was stabbed to death after argument about the suspect's sister, court documents show

Cash App founder Bob Lee was fatally stabbed by an IT consultant near downtown San Francisco after the two men — who police say knew each other — got into an argument over the suspect's sister, according to court documents obtained Friday by NBC News.

The suspect — 38-year-old Nima Momeni of Emeryville, a suburb of San Francisco — drove Lee to a secluded area and stabbed him three times with a 4-inch kitchen knife, including twice in the chest, according to the documents. At least one of the stab wounds punctured Lee's heart.

At one point, Momeni's sister sent a text to Lee, the documents show. “Just wanted to make sure your doing ok Cause know nima came wayyyyyy down hard on you," she wrote, according to the documents.

"Thank you for being such a classy man handling it with class," she added. "Love you Selfish pricks."

Momeni was arrested on Thursday morning after a nine-day manhunt that attracted national attention and intensified scrutiny on public safety issues in the Bay Area.

He will be charged with murder, San Francisco's district attorney told reporters on Thursday. He is scheduled to be arraigned on April 25, a spokesman for the district attorney's office confirmed, and he faces 26 years to life behind bars if convicted.

The court documents, which the San Francisco district attorney's office filed Friday as part of its attempt to detain the suspect without bail, piece together the events that led to the stabbing.

Lee and a friend interviewed by police had been hanging out in a hotel room in San Francisco on the evening of April 3, prosecutors said in the documents. The friend, identified in the filings as Witness 1, noticed Lee having a conversation with Momeni.

The witness heard Momeni asking Lee whether Momeni's sister had been "doing drugs or anything inappropriate" earlier that day. Lee had to "reassure" Momeni that "nothing inappropriate had happened," according to the documents.

Later that night, a surveillance camera recorded Lee and Momeni getting into Momeni's white BMW outside his sister's apartment. Additional footage obtained by police shows the BMW heading to a "dark and secluded area" near downtown San Francisco.

The two men are later seen standing together on a sidewalk for a few minutes before Momeni apparently stabs Lee. Momeni then tossed the knife, got back in his car and sped away.

When police officers arrived at the scene around 2:30 a.m., according to the documents, they found Lee unresponsive, lying in the street and bleeding "uncontrollably." When officers returned to canvass the area, they found the blood-stained knife.

"Defendant did not use some type of pocket knife, but a cooking knife from an apartment and kitchen," the court documents state. "This was a planned and deliberate attack."

The revelation that Lee and Momeni knew each other has undercut speculation that the Cash App creator was killed in a random act of violence.

The tech mogul Elon Musk, in a tweet that drew the condemnation of the district attorney, appeared to pin the blame for the killing on "repeat violent offenders."

Momeni describes himself as an entrepreneur on his LinkedIn page. He lists himself as the owner of a tech company called Expand IT Inc. and as a graduate of the University of California, Berkeley.

However, a spokesperson for U.C. Berkeley told NBC News on Friday that the university has "no record of graduation or attendance" for a person named Nima Momeni.

Lee had been working as the chief product officer of the cryptocurrency company MobileCoin. He was previously the chief technology officer of Square (now known as Block), a financial technology firm co-founded by the former Twitter head Jack Dorsey.

He went on to create Cash App, a well-known money transfer service.

Lee also was an investor in Musk’s SpaceX venture, as well as other tech companies, such as the social audio app Clubhouse, according to his LinkedIn profile.