“Let’s pretend that I’m 10 years old … how would you explain to a 10-year-old what it is that we’re doing?” asked San Francisco Superior Court Judge Alexandra Gordon who, along with a full jury box, had been listening to testimony from San Francisco police criminalist Alain Oyafuso since late morning.
Oyafuso, yet again, tried to explain the DNA he analyzed on the knife that allegedly killed Cash App founder Bob Lee in April 2023 — and how most of the DNA on the blade matched Lee’s, and most of the DNA on the handle matched that of his accused killer, Nima Momeni.
He used terms like “proposition of inclusion” that clearly befuddled the judge and jurors, but referred to the likelihood of a DNA match. Jurors asked several follow-up questions after attorneys finished.
Attorney Zoe Aron: Your opinion of the results is that Mr. Momeni’s DNA is on the handle?
Oyafuso: … Because we never can say that the exact individual is the source of something, but the proposition of [inclusion] is a very strong support for that.
Aron: And for the blade, there’s very strong support that Mr. Lee’s DNA is present?
Oyafuso: There is very strong support for the proposition of inclusion.
When it came to examining the handle of the knife, Oyafuso said, “Momeni best fits the data for the contributor, who contributed 99 percent of the total.” That conclusion, he said, had a likelihood of 1.66 septillion — which has 24 zeroes.
But it’s more complicated than that: Both handle and blade had a small amount of low-quality DNA from another person, or “contributor,” which Momeni’s defense team used to cast doubt on the narrative of Momeni simply stabbing Lee. Momeni has claimed Lee attacked him, and he stabbed Lee in self-defense.
According to DNA analysis shown to the jury today, there was “very strong support” that Lee’s DNA matched that on the blade and Momeni’s matched that on the handle. There was, meanwhile, just “limited support” to exclude each man’s DNA from the opposite ends of the knife.
Aron: If someone were to say that there was only one person’s DNA on the blade, that’s incorrect.
Oyafuso: There is indications of at least two people on the blade.
Aron repeated the question, and Oyafuso said: “Another analyst may have an argument for it one way or the other but, in my opinion, they also confirmed two. So, you never know the true number.”
Momeni’s attorney, Saam Zangeneh, said afterwards that he thought “everybody in that courtroom was confused” by Oyafuso’s technical explanations. At one point, Oyafuso asked Judge Gordon if his statement made sense, and the judge began to playfully sob.
“No, no!” Gordon wailed. Shortly after, she clarified: “I’m not actually going to cry.”
Zanganeh, Momeni’s defense attorney, said “DNA helps when it’s a ‘whodunit,’” to identify a suspect who may be missing from the evidence otherwise. But “this isn’t a whodunit,” he said. “We know [Momeni is] there, we know we have video, we’re admitting he had the knife — he threw it over the fence.”
He said it made sense for Lee’s DNA to be on the blade, but as to the handle, while “Nima was the last person to touch it … we don’t know the situation, we don’t know the circumstances.”
The defense does not dispute the fact that Momeni stabbed Lee. It’s just a question of whether Lee held the knife handle first. It reads to me that he did not.
Many other news outlets report a much clearer picture, for example:
“Expert says 99% of DNA found on handle of knife that killed Bob Lee belongs to Nima Momeni”
If the prosecutors screw this up 99% of blame will be on them.
It’s pretty common for news outlets to report a picture that’s clearer and simpler than the truth, and that sounds like an example. That tends to set readers up for frustration when decision-makers who have a fuller picture — like a jury — don’t do the thing that seems obvious from the simple picture. I appreciate Mission Local giving us an accurate picture of what was said in court, as confusing as it may be.
This person on the stand, though, definitely needs to get better at explaining the nuances clearly for a courtroom audience, instead of relying on befuddling terms like “proposition of inclusion”. I hope after this trial is over he spends some time practicing that. Maybe the DA’s office can help.