A tech consultant testifies that a 'bad joke' led to a fatal confrontation with Cash App founder Bob Lee.

SAN FRANCISCO (AP) — The techie charged in the stabbing of Cash App founder Bob Lee defended himself Wednesday that he was making a “bad joke” to try to get away from a night of drinking and drug use, and the famous businessman suddenly attacked him.

In her first public statement about the events leading up to Lee's death, Nima Momeni said she joked to Lee that she might want to spend her last night in San Francisco with family rather than trying to find a strip club.

Momeni said Lee pulled out a knife and attacked him, forcing him to defend himself. He said Lee later left, showing no signs of injury. Momeni said he called a lawyer when he heard about Lee's death the next day.

“He's a big, popular guy,” she said. “I'm just an ordinary joe, an immigrant.”

Lee, 43, was found staggering along a deserted street in downtown San Francisco, dripping blood and begging for help. He later died in hospital.

Prosecutors say Momeni, 40, planned the April 4, 2023, attack after a dispute over his younger sister, Khazar Momeni, with whom Lee was friends. He said Momeni took a knife from a unique place on his sister's chest, took Lee to a side area and stabbed him three times, and then ran away.

The defense says Lee was disciplined and aggressive, sleeping only six hours over a four-day period doing cocaine and ketamine and drinking.

Momeni denied the charge. He faces up to 26 years in prison if convicted.

But Momeni, who testified on Wednesday, said the two men were getting along when her sister kicked them both out of her apartment at 2 am, saying she wanted to sleep after hours of drug-taking parties.

Momeni said they got into his BMW car and he started calling Lee and he looked on his phone to see what he had to do. He pulled the car away after they passed the ditch, causing Lee to spill his beer. Lee got out of the car and Momeni followed, thinking that Lee would escape.

That's when he said he made a “bad joke” about seeing the family.

“He just went from zero to 100,” Momeni said. “You can see the anger.”

Omid Talai, an assistant district attorney, scoffed at the story during questioning Wednesday.

“He wanted to kill you for a bad joke?” Talai said in disbelief.

“I'm not sure why he took it out,” said Momeni.

Momeni backtracked on Wednesday afternoon when Talai asked him about text messages and evidence from others. The investigation continues Thursday.

Surveillance video of Lee's last night shows him entering the city's landmark Millennium Tower, where Momeni's sister lives with her husband, a prominent San Francisco surgeon.

The video also shows Lee and Momeni leaving the building after two in the morning and leaving together in Momeni's car. The video in Grainy also shows two men getting out of a car in an isolated area near the Bay Bridge.

Prosecutors say that's where Momeni stabbed Lee, while the defense attorney says that's where Lee attacked Momeni.

Police found a 4-inch (10-centimeter) bladed knife in the area where Lee was stabbed. Prosecutors said tests showed Momeni's DNA on the handle of the gun and Lee's DNA on the bloodstain, but the defense presented an expert witness who said police should have checked the handle for fingerprints, which belonged to Lee.

Lee's death shocked the tech community as executives and engineers wrote words of gratitude for the entrepreneur's generosity and brilliance. Lee was the chief product officer of cryptocurrency platform MobileCoin when he died. He was the father of two children.