📄 Motion: DNA mixture analysis — Wednesday, May 10, 1995
Address:
C:\DEPT103\CRIMINAL\1995\MAY\10\MOTION-DNA-MIXTURE-ANALYSIS.DOC
TRIAL
▲ Day 71 of 167

Motion: DNA mixture analysis

Date: Wednesday, May 10, 1995 • Utterances: 25
Defense attorney Peter Neufeld argued that the prosecution must present statistical frequency data when presenting DNA mixture evidence, or the jury will be misled into assuming the same astronomical odds (one in eight billion) apply to mixtures as to single-source samples. Judge Ito ruled in the defense's favor, ordering the prosecution to present some type of statistical analysis alongside the mixture evidence. The legal debate centered on People v. Barney and the NRC report as authority for requiring DNA statistics.
1 THE COURT:

All right. Dr. Cotton, you can step down.

2 (Witness complies.)
3 THE COURT:

All right. Mr. Clarke, any comment briefly?

4 MR. CLARKE:

Yes. Just briefly, your Honor. I think under these circumstances, and as the witness has already noted, that under the specific circumstances of the testing involved, and we are looking at item no. 78, in particular, that under those circumstances, particularly when one takes into account the RFLP typing pattern--

5 THE COURT:

Well, Mr. Clarke, let me ask you this: Assuming that because of the manner in which Dr. Cotton just testified, that it is not inappropriate to testify both that these persons are not excluded and on cross-examination be cross-examined as to the population frequencies in an aggregate, don't we come to the same information; you get to do it your way on direct and they get to cross-examine?

6 MR. CLARKE:

I think that goes back to the actual objection itself. The objection was to the board and I think we need to put that back into its proper perspective. That was the objection. My intent is to ask the witness basically what the Court just heard, can you exclude these people? No, I can't. Are there also other types, you know, other groups of people that you cannot exclude? That is certainly true, they have different genotypes, and I think that is an appropriate way of characterizing it and I think if the Defense wants to elicit from the witness frequency data summing it up and obtaining what other number, they have a right to do that because I think that is general redirect examination and cross-examination.

7 THE COURT:

All right.

8 MR. NEUFELD:

Your Honor, two things: Umm, first of all, I would note that I did have a chance last night to look at the cases that were cited by Mr. Harmon, and neither of them stands for the proposition that--you know that already.

9 THE COURT:

I don't--I did not find them to be germane.

10 MR. NEUFELD:

Okay. I agree. Your Honor, the issue here is not what the Defense can do on cross-examination. The issue is, no. 1, what does the law of California compel? And no. 2, what does the scientific literature which is unrefuted state is obligatory on the part of somebody trying to present data? And on both those points there is unanimity that if they wish to present data--

11 THE COURT:

Well, Barney is dicta, counsel.

12 MR. NEUFELD:

Well, I don't think it is dicta in Barney that DNA evidence without a number is meaningless. I think what they are simply saying is that statistics have to be reported. That is also the--frankly, when you read the NRC report, that is one of the most important recurring themes in the entire, you know, 150 pages. And no one has ever--no one is questioning that here. Umm, your own ruling in fact explicitly so held back in April.

13 THE COURT:

In a much different context.

14 MR. NEUFELD:

Well, the NRC report and Barney makes no distinction between mixed stains and stains that allegedly come from a single source. More importantly, your Honor, what we are concerned with is how is the jury going to accept all this? And if on the one hand you have them describing numbers of one in eight billion or one in 25 billion, for a particular profile, with--say it is consistent with one person and then in the very next box they describe a mixture and say that we can't exclude Mr. Goldman or we can't exclude Nicole Brown Simpson, umm, the jury will draw the logical inference that the same kind of statistics apply there as well. It is not incumbent on me as a Defense attorney to debunk that misstatement of the objective data. They have an independent duty not to mislead or confuse the jury long before we ever get to cross-examination. That is what Barney recognizes. That is what the NRC report recognizes. What Robin Cotton has told us is that, yes, those numbers can be calculated and they can be calculated without a great deal of difficult. With regard to the stain on the steering wheel, 29, I sat down and did it in about fifteen minutes. Certainly they can do that for both item 78 and item 29 and those numbers can be presented to the jury. And if they choose not to present the numbers, which is required by the report and part of the decision in Barney, they should simply be precluded from putting on that evidence as to those mixtures. The reason they don't wish to put on those numbers is they want to mislead the jury. If they didn't want to mislead the jury, they would do what is considered scientifically acceptable. Robin Cotton did not cite a single authority to say it is scientifically acceptable to put on DNA evidence of a match in a mixed stain without reporting a frequency. That is the point here. And that is the simple thing we are asking the Court to decide and to compel the People to do, and if there is no authority to the contrary, I don't see why either in logic or law they should be allowed to do something which does have the effect of confusing and misleading this jury. That is all we are asking for. We are not saying they can't present any evidence of mixtures. Let them present them but present them in a fair and impartial way. And what they are doing is misleading the jury. It is not fair and it is not impartial.

15 MR. CLARKE:

Two comments. I can guarantee to the Court that there will be differences between the sides about what those numbers are. I don't think the matter is nearly as simple as Mr. Neufeld would have the Court believe. That is the first observation. The second observation is, and it is interesting to hear the discussions about People versus Barney, because Barney appears to be dying under the weight of authority that has happened since then. As the Court provided to counsel today--

16 THE COURT:

Yes. The met news reports that Barney is mentioned disparagingly.

KEY QUOTE
17 MR. CLARKE:

And as was the case with conventional serology back in the 1980's when Mr. Harmon and I became involved in this area, it appears that by the weight of authority again courts are accepting the original testing the way it was done. So I think to use Barney in the context of a mixture or to use the NRC report in 1995 based on evidence provided in 1990 and 1991 and early `92 to describe where we are today, and to turn that into a compulsion that a witness provide a frequency that the Court has already heard, she doesn't feel is frankly a perfectly fair way of approaching it, as opposed to describing the facts that certain people are excluded, certain people are not excluded. And to allow the Defense to elicit testimony in a manner that they feel is appropriate under these circumstances is, frankly, the criminal justice system by itself.

18 THE COURT:

All right. Thank you, counsel.

19 MR. NEUFELD:

Just one. Just in regard to the cases that you handed out today, I would just like to comment on that and limit it to that.

20 THE COURT:

To the case that was brought out today? All right.

21 MR. NEUFELD:

Just, your Honor, those cases where they distinguish or talk about Barney are only talking about Barney's comments on the product rule versus the ceiling approach. There is absolutely no comments in any of those cases disparaging the need to have some kind of statistical significance to the meaning of DNA, be it in a mixed stain or a single stain, and that is an important point here. That is what we are talking about and I haven't seen any legal authority to the contrary on that.

22 THE COURT:

All right. The Court is going to require the Prosecution to present some type of statistical analysis with regards to the mixtures. All right. Let's have the jury.

KEY QUOTE
23 MR. CLARKE:

Your Honor, may we have a short recess for the witness?

24 THE COURT:

All right. We've been going for a while. Let's take a recess.

25 (Recess.)

Temperature

tense

Key Quotes (4)

Peter Neufeld
If on the one hand you have them describing numbers of one in eight billion or one in 25 billion, for a particular profile, with--say it is consistent with one person and then in the very next box they describe a mixture and say that we can't exclude Mr. Goldman or we can't exclude Nicole Brown Simpson, umm, the jury will draw the logical inference that the same kind of statistics apply there as well.
Core argument for why presenting mixture evidence without frequencies is inherently misleading — the jury will fill in the gap with the dramatic single-source statistics
Peter Neufeld
The reason they don't wish to put on those numbers is they want to mislead the jury.
Direct accusation of prosecutorial bad faith — unusually blunt for a motion argument
Lance A. Ito
The Court is going to require the Prosecution to present some type of statistical analysis with regards to the mixtures.
The ruling — defense wins this motion, forcing the prosecution to calculate and present frequency data for mixed DNA stains including items 78 and 29
Lance A. Ito
The met news reports that Barney is mentioned disparagingly.
Judge signals he has researched the case law and is skeptical of Barney's continued authority, though he ultimately rules in the direction Neufeld argues

Evidence (2)

Informal
Item 78 — DNA mixture sample, central to the dispute over statistical reporting
discussed
Informal
Item 29 — steering wheel stain, another DNA mixture; Neufeld claimed he personally calculated the statistics in fifteen minutes
discussed

Notable Exchanges (3)

Peter NeufeldLance A. Ito
Neufeld argued Barney requires statistical significance for all DNA evidence including mixtures; Ito pushed back that Barney is dicta and was decided in a different context, but ultimately ruled for the defense anyway
strategic
George ClarkeLance A. Ito
Clarke argued Barney is dying under the weight of subsequent authority and courts are returning to accepting DNA testing without mandatory frequency reporting; Ito noted the met news coverage disparaging Barney before overruling Clarke's position
strategic
Peter NeufeldGeorge Clarke
Clarke warned that the two sides would disagree on what the mixture statistics actually are, suggesting the calculation is not as simple as Neufeld claimed; Neufeld countered that Cotton herself said the numbers could be calculated without great difficulty
heated

Witness Demeanor

(Witness complies.) — Dr. Cotton steps down at Ito's direction

Objections

None recorded
Proceeding 5994 • 25 utterances
Criminal Trial
Department 103
⚖️ Start
📂 MAY 10, 1995 📄 Motion: DNA mixture analysis
MAY 10, 1995 KRT DvH TD