Nima Momeni, an IT consultant, fatally stabbed CashApp founder Bob Lee through the heart after both men argued about the suspect’s sister — and whether they were doing “anything inappropriate,” according to new court documents released Friday.

According to police, Momeni and Lee spoke on the phone about his sister, Khazar Momeni, who was married to someone else before Lee was murdered on the streets of San Francisco in the early hours of April 4.

According to an unnamed witness, Nima questioned Lee about his sister, Khazar, who is married to a prominent plastic surgeon, and whether she was “doing drugs or anything inappropriate.”

Lee, 43, assured his alleged murderer that nothing out of the ordinary had occurred.

The police did not go into detail about Lee’s relationship with Khazar, who was not named in the court documents.

According to the witness, it was unclear whether Lee and Khazar had a “intimate relationship.”

At the time of his murder, Lee was estranged from his wife, with whom he had two young daughters, and had relocated from California to Florida with his father.

According to the charging documents, Nima drove Lee to a “dark and secluded area” of San Francisco that fateful night and stabbed him through the heart with a kitchen knife.

Khazar brought the knife from his home, which police say proves the murder was “planned and deliberate.”

According to the documents, Khazar texted Lee around the time of his murder to check in on him.

“I just wanted to make sure you were okay because I know Nima came down hard on you,” she wrote.

“And thank you for being such a gentleman in dealing with it. I adore you selfish jerks.”

Nima was arrested Thursday morning after an extensive investigation, and he appeared in court for the first time on Friday, accompanied by his sister and her husband. From the dock, he flashed a heart symbol to her, and she responded with the same symbol. Nima is scheduled to be formally arraigned on April 25, and if convicted, he faces more than 20 years in prison.

Lee was estranged from his wife, with whom he had two young daughters, and was living with his father in Florida at the time of his murder.

Nima was arrested early Thursday, and prosecutors intend to charge him with murder.

He is scheduled to be arraigned on April 25, and if convicted, he faces more than 20 years in prison.

According to police, Lee went between Khazar’s multi-million dollar high-rise apartment during the afternoon of April 3, where they drank alongside a witness and someone else who lived in the apartment.

Police have since searched that apartment.

The witness and Lee then returned to the tech titan’s hotel room in San Francisco, where he spoke on the phone with Nima.

The pair then went to Lee’s apartment also in San Francisco, where they hung out for a while.

The pair then went to Lee’s apartment, also in San Francisco, where they hung out for a while.

At 12:30 a.m., Lee left his own apartment.

Lee was never seen by the witness again. The relationship between Lee and the witness was not explained by police, but the two had known each other for about a decade.

The witness called Khazar on April 4 and asked if Lee had gone over, not knowing where he went.

The sister said yes, but only stayed “for a second” before falling asleep and not knowing where he went.

Lee returned to Khazar’s place in the early morning of April 4, according to video footage from her sister’s apartment.

It also shows him and Nima in the ritzy building’s elevator together at 2:03 a.m., before the two got into the alleged killer’s white BMW.

Authorities said grainy video captured Lee and Nima standing outside the BMW for about five minutes in a deserted part of the wealthy Rincon Hills neighborhood shortly after.

That is when it is believed Nima stabbed Lee “three separate times,” according to prosecutors’ motion to detain the suspect without bail.

“One of the wounds, showing a direct and clear intent to kill, penetrated the Victim’s heart,” wrote Assistant District Attorney Omid Talai.

Additional security cameras appear to show Lee walking away injured and Nima walking near the area where the murder weapon was discovered, but the video isn’t clear enough to show their faces. 

The white BMW then sped off at a high speed, police say, and Lee was left “to slowly die.”