The sister at the heart of the murder case against Nima Momeni, in which Cash App founder Bob Lee was killed in downtown San Francisco in April, was caught up in an alleged crime of a different nature on Monday morning in SF.

Khazar Momeni, 38, who also goes by her married name Khazar Elyassnia, was arrested Monday on suspicion of DUI in San Francisco's Tenderloin district. As the Chronicle reports via the SFPD, police officers responded to a report of a vehicle collision at Larkin and Geary streets at 11:08 a.m.

The circumstances of the crash have not been reported. But we know that after taking witness statements and talking to Momeni herself, police arrested her on suspicion of DUI, hit and run, failing to drive within a lane, and failing to provide proof of financial responsibility.

Khazar Momeni is expected to remain a central figure in the case against her brother, and in the narrative about what transpired the day and that Lee was killed. Once the trial finally gets underway, likely sometime next year, the prosecution is expected to argue that Nima Momeni killed Lee out of anger over something that happened to his sister while she was with Lee — and that possibly involves the actions of a third individual, identified as Lee's drug dealer.

In court documents and witness statements revealed so far, we know that Lee and Khazar Momeni, who previously had had a romantic relationship, were at a party in a SoMa apartment together on the afternoon of Monday, April 3. Momeni reportedly woke up, possibly after being drugged, partially clothed in a bedroom at this party, and went home upset to her condo in Millennium Tower, which she shares with her husband, plastic surgeon Dr. Dino Elyassnia.

She allegedly called her brother, who went to see her at her home. Hours later, around midnight, they summoned Lee to the condo — Lee had been staying at 1 Hotel on the Embarcadero. And Lee and Momeni are seen on surveillance video leaving the condo together around 2 a.m. and getting into Momeni's car.

Around 20 minutes later, surveillance video captured, from a distance, what may have been the murder scene under the Bay Bridge, near Rincon Hill. And Lee then stumbled toward the Portside II building on Main Street, bleeding, and seeking help. He would later succumb to his injuries, which included a stab wound to the heart.

The murder weapon, police have suggested, was a kitchen knife that had been taken from Khazar Momeni's condo.

A text sent from Khazar Momeni's phone to Lee after he had left with her brother is expected to figure heavily in the case as well. In it, she wrote, "Just wanted to make sure your doing ok cause I know Nima came wayyyyyy down hard on you and thank you for being such a classy man handling it with class love you selfish pricks."

Nima Momeni has been denied bail, and he is expected back in court Thursday, at which point a trial date may be set.

Previously: Judge Rejects Defense Theories In Bob Lee Stabbing; Date-Rape Drug Allegation Emerges; Nima Momeni to Proceed to Trial

Photo: Khazar Elyassnia (C) arrives for the arraignment of her brother Nima Momeni on May 18, 2023 in San Francisco, California. 38 year-old tech entrepreneur Nima Momeni was arraigned today in a San Francisco courtroom in connection with the stabbing murder of Cash App founder Bob Lee. Momeni pleaded not guilty to a murder charge. (Photo by Justin Sullivan/Getty Images)