Nima Momeni's DNA on handle of knife, jury told in murder trial

San Francisco - San Francisco police criminalist Alain Oyafuso took center stage in the Nima Momeni murder trial on Thursday. 

Oyafuso, who specializes in DNA analysis, testified, in essence, that Momeni's DNA was found on the handle of a Joseph Joseph-brand knife, and that the blood on the blade belonged to the victim, Cash App founder Bob Lee.

The prosecution says the defendant tossed that knife over a fence after stabbing Lee in April 2023. Authorities say a second Joseph Joseph-brand knife was found in the kitchen of Momeni's sister's apartment.

But the defense says it was Lee, during a drug-fueled bender, who was aggressive and came at Momeni with a knife, and that Momeni then took the knife and stabbed Lee in self-defense. 

KTVU legal analyst Michael Cardoza says if that's the case, then it should come as no surprise that both men's DNA was found on the knife.

"So the defense has to be awfully careful not to bore the jury and lose credibility with them. Now the fact that who brought the knife, that's an important question," Cardoza said. "But DNA really doesn't have anything to do with that, in my mind. 

Saam Zangeneh, one of Momeni's five attorneys, says the defense doesn't dispute that Momeni touched the knife. But he said the DNA expert testified a small percentage of DNA on the handle belonged to someone else. 

"If this was a whodunit, my client would be in trouble. It's not," Zangeneh said. "So I think it's one of their strongest or at least what they felt was one of their strongest pieces of evidence, I think that has been substantially deflated."

The trial resumes on Monday.

Henry Lee is a KTVU crime reporter. E-mail Henry at Henry.Lee@fox.com and follow him on Twitter @henrykleeKTVU and www.facebook.com/henrykleefan