Cash App founder Bob Lee dated his murder suspect's ex-girlfriend before he started seeing his sister, friends said. The suspect's lawyer disputes claims of an affair.

• Nima Momeni is facing a murder charge in connection to the death of Cash App founder Bob Lee.
• Lee dated Momeni's ex-girlfriend about three years ago, sources told The Wall Street Journal.

Cash App founder Bob Lee dated his murder suspect's ex-girlfriend before he began casually sleeping with the alleged killer's sister, Khazar Momeni, friends familiar with Lee's relationships told The Wall Street Journal.

Nima Momeni, a 38-year-old tech consultant, faces a murder charge in connection to the fatal stabbing of Lee on April 4 in San Francisco.

Prosecutors previously alleged in court documents that Momeni confronted Lee that night about his sister, Khazar, before the stabbing. According to a witness that evening, Momeni asked Lee if his sister "was doing drugs" or "anything inappropriate."

Lee's friends told WSJ that Khazar — who is married — was having an affair with Lee, but the Cash App founder's connection to his suspected killer goes back further: About three years ago, Lee was dating Momeni's ex-girlfriend, the friends claimed.

Keith Kraft, a mutual friend of both Lee and the unnamed woman, told the newspaper she started seeing Lee after splitting up with Momeni. It's unclear how long after the woman broke up with Momeni before she started dating Lee.

Kraft said he recalled Momeni giving him dirty looks when he spent time with the woman, which he thought suggested Momeni was a jealous person: "Look, bro, I'm gay, I'm not a threat to you," Kraft recalled telling Momeni.

He added that Momeni may have had "some major insecurities going on." Kraft did not respond to Insider's request for comment.

Afterward, friends familiar with the matter said that Lee started sleeping with Khazar Momeni, who is married to Dino Elyassnia, a well-known San Francisco-based plastic surgeon. The timeline of their alleged affair is unclear. An attorney for Elyassnia and Khazar did not respond to a request for comment.

Suspect's attorney disputes alleged affair

In a call with Insider, Momeni's lawyer, Paula Canny, disputed the information people provided to WSJ, including the alleged affair between Lee and Khazar.

"Based on my investigation, there was no romantic or sexual relationship between (Khazar) and Bob," Canny said, adding that she didn't know what Lee may have told other people about this supposed relationship. She declined to reveal to Insider what information she had to conclude Lee and Khazar were not having an affair.

Canny, who remains in contact with Momeni's family, also said she isn't aware if Lee and Momeni had the same partner. If they did, Momeni may have been unaware of it, Canny said.

"If Nima and Bob had ever dated the same person ... I wasn't aware, and it had no significance," Canny said.

It's unclear if Momeni might have heard of Lee through the alleged mutual ex-partner. According to a report from Mission Local, Momeni only knew Lee through his sister, who had known the Cash App founder for several years.

Momeni faces a murder charge with a sentencing enhancement due to the kitchen knife police say was used in the incident. The stabbing was a "planned and deliberate attack," prosecutors alleged in court documents.

An autopsy report from the San Francisco Office of the Chief Medical Examiner showed that Lee died from three stab wounds. The report also found the presence of alcohol, ketamine, and cocaine in Lee's system.

Canny pointed to the toxicology report and told reporters after a May 2 court hearing that Lee's system was "the Walgreens of recreational drugs," suggesting it may be relevant to her client's defense.

Friends told WSJ that Lee was part of an underground party scene known as "The Lifestyle," which included recreational drugs and casual sex, for several years.

"It started with the hippies, who were not sober people, trying to expand their brains and the tech people came in and gentrified it like they did everything else," said Harper Reed, the CEO of General Galactic Corporation, a fintech startup, and Lee's friend, told WSJ.

Sources close to Lee also told the newspaper that Lee attended raves and took ecstasy, ketamine, and cocaine.

Lee's wife, Krista Lee, who remained close to the Cash App founder even after their separation, disputed statements painting Lee as a "party boy." She told WSJ that, if anything, Lee may have been microdosing ketamine to treat depression.

"He was kind and generous—he saw the good in everybody," Lee's wife told the newspaper. She added that "he was a dedicated father. He was more mature than that."

Krista Lee did not immediately respond to a request for comment.