Cross-examination of John Gerdes (part 2)

📄 Cross-examination of John Gerdes (part 2) — Thursday, December 12, 1996

Address:

C:\DEPT103\CIVIL\1996\DEC\12\CROSS-EXAMINATION-OF-JOHN-GERD.DOC

TRIAL

▲ Day 31 of 57

◀ Sidebar: Promega article admissibility Cross-examination of John Gerdes (part 1) ▶

Witness: Dr. John Gerdes
Examiner: Daniel Petrocelli
Called by: Defense • Date: Thursday, December 12, 1996 • Lines: 116

Mr. Lambert questioned Dr. Gerdes about DNA results from the Bronco, glove, socks, and Bundy blood-drop evidence. Gerdes agreed that Item 52 was the only RFLP result he disputed on contamination grounds, while maintaining that PCR matches in the glove's wrist area might have resulted from contamination. Lambert then used Exhibit 2265 to question Gerdes about Yamauchi's controls, and Gerdes agreed that the controls were negative for DNA.

# 1 THE COURT:

Ladies and gentlemen, I want to announce a disclaimer. That's not my chambers.

# 2 (Laughter.)

# 3 THE COURT:

I'm borrowing that chambers. And all the art work and everything, except for - Are not mine.

# 4 (Laughter.)

# 5 MR. PETROCELLI:

Inside joke, Your Honor.

# 6 THE COURT:

You may proceed.

# 7 Q:

(BY MR. LAMBERT) We need to get the Bronco board.

# 8 MR. FOSTER:

293 again.

# 9 MR. PETROCELLI:

293, Gina.

THE COURT REPORTER: Okay. Thank you.

# 10 (Exhibit 293 is displayed.)

# 11 Q:

(BY MR. LAMBERT) Dr. Gerdes, before the brief break, we were talking about none of these evidence items that are consistent with Mr. Simpson on this particular board could have come into contact with the reference vial of Mr. Simpson and be explained by cross-contamination from that vial, correct?

# 12 A:

Correct.

# 13 Q:

So your only theory as to how any contamination could possibly account for these results is if some of the Rockingham evidence samples caused this contamination, correct?

# 14 A:

Correct.

# 15 Q:

And that would mean that the Rockingham samples were also consistent with Mr. Simpson's blood, correct?

# 16 A:

That's correct.

# 17 Q:

And the -- once again, the -- this RFLP result down here, you're not saying that was a result of contamination, are you, Dr. Gerdes?

# 18 MR. BLASIER:

Objection. Beyond the scope.

# 19 THE COURT:

Overruled.

# 20 A:

In that particular case, that there -- there's a very minor component. I think Dr. Cotton's testimony was about 20, or Gary Sims' testimony was around 20 nanograms of DNA in there. And it's when you combine things of that -- in that nature, I think there is a risk of -- of picking up a contaminant, especially when he estimates that the -- The RFLP results were based on just 20 nanograms of DNA.

# 21 Q:

(BY MR. LAMBERT) But that's just theoretical, right?

You didn't see anything in the results to indicate contamination?

# 22 A:

No I didn't, no.

# 23 Q:

You're saying that's a, well, very --

# 24 A:

I'm saying it's a risky kind of thing to do when you're trying to combine things, and you're working with very small quantities of DNA like that.

# 25 Q:

But the RFLP results are basically consistent with the prior PCR results from the same blood stain?

# 26 A:

The appearances are consistent, yes.

# 27 Q:

Okay.

Now, this is the result from Rockingham. And as to this five-probe match, you're not saying that that was caused by any contamination, correct?

# 28 A:

No.

# 29 Q:

Now, are you saying that either of these results were caused by contamination?

# 30 A:

Which two are you talking to, number 6 and number 7?

# 31 Q:

Number 6 and 7.

You're not saying that either 6 or 7 is caused by any contamination, correct?

# 32 A:

That's correct.

# 33 Q:

So when Cellmark and DOJ got those items and tested them. They got the correct results?

# 34 A:

Yes.

# 35 MR. BLASIER:

Objection. Foundation.

# 36 THE COURT:

Excuse me.

Overruled.

# 37 Q:

(BY MR. LAMBERT) And you have no basis for saying that when those evidence items were processed by LAPD, that they did anything to cause any contamination?

# 38 A:

There's no direct evidence of that.

KEY QUOTE

# 39 Q:

Let me show you a couple more boards quickly here.

# 40 (Exhibit 295 was displayed.)

# 41 MR. FOSTER:

320.

# 42 (Plaintiffs' Exhibit 320 displayed on the Elmo screen.)

# 43 MR. LAMBERT:

This it which exhibit?

# 44 MR. PETROCELLI:

320.

# 45 Q:

(BY MR. LAMBERT) This is the board showing the results of the DNA analysis on the glove. And here again, we see several RFLP matches, correct, Dr. Gerdes?

# 46 A:

Yes.

# 47 Q:

And once again, you would agree those could not possibly be caused by contamination, correct?

# 48 A:

The RFLP, no.

# 49 Q:

Yes, sir.

Now, you, in regard to the PCR matches here, are you saying that any of those might possibly be caused by contamination?

# 50 A:

Yes.

# 51 Q:

Which ones?

# 52 A:

In the wrist area, the matches with Mr. Simpson -- that's the area that was handled immediately after the reference sample? That's the one where there's a possibility of that happening.

# 53 Q:

Well, Collin Yamauchi didn't handle just the wrist area, did he?

# 54 A:

No. He handled other areas, as well.

# 55 Q:

Right.

So you would think if he was contaminating the wrist area, he would have contaminated other areas, as well?

# 56 A:

Not necessarily. Other areas may have had more competing DNA. It's a matter of how much DNA was transferred, and what the background DNA that he's amplifying the presence of, that's the state of that.

# 57 Q:

But it seems likely that if he was contaminating the wrist area of the glove, he either would have contaminated other areas on the glove or the control swatch that he handled immediately after that. Isn't that true, doctor?

# 58 A:

That's a possibility.

# 59 Q:

And let's finally look at RFLP results on the socks.

# 60 MR. PETROCELLI:

299. Referring to 299.

# 61 (Plaintiffs' Exhibit 299 displayed on the Elmo screen.)

# 62 Q:

This -- the results board on the socks found at Rockingham.

You agree, Dr. Gerdes that those RFLP results obtained by Cellmark and DOJ are not possibly caused by contamination, correct?

# 63 A:

That's correct.

# 64 Q:

And, in fact, this 11-probe and 5-probe match together between Cellmark and DOJ showing the blood of Nicole Brown Simpson was on those socks. That's an extremely probative RFLP result.

# 65 MR. BLASIER:

Objection. Argumentative. Calls for legal conclusion.

# 66 THE COURT:

Overruled.

# 67 A:

Yes, it is.

# 68 Q:

MR. LAMBERT: And the nine-probe match showing Mr. Simpson's blood is also on the socks.

That's a very significant result, isn't it, Dr. Gerdes?

# 69 A:

It is.

# 70 Q:

And do you have any reason to believe that any of the PCR results on those socks are the subject of contamination?

# 71 A:

No.

# 72 Q:

So of all of the RFLP results --

# 73 MR. PETROCELLI:

For the record, that's Exhibit 299.

# 74 Q:

(BY MR. LAMBERT) -- of all of the RFLP results, the only one that you have any quarrel with at all is item 52?

KEY QUOTE

# 75 A:

That's correct.

# 76 Q:

We probably don't need any more. (Indicating to boards.)

Item 52 was one of the five Bundy blood drops, correct?

# 77 A:

That's correct.

# 78 Q:

And what's your basis for stating that that could have been caused by contamination, even though it's an RFLP result?

# 79 A:

Well, there's several different aspects.

Number one, extremely degraded sample -- there's a very small amount of analyzable DNA. And it's at -- on the borderline of what's a level that you can actually do an RFLP on.

And so because there's a very small amount of DNA there, the concentration of DNA, at least in the range in which, theoretically, you could have cross-contamination.

The second thing is the fact that it was handled at that time subsequent to, or at the same time as the reference sample. And from experience of other laboratories, that's a situation where you have an extreme risk of the possibility of cross-contamination.

# 80 Q:

Okay.

# 81 A:

There's errors, where that has been shown to be the cause of those errors.

# 82 Q:

So you're saying that's a low amount of DNA in that particular RFLP result, correct?

# 83 A:

Very small amount of analyzable DNA, highly degraded sample.

# 84 Q:

About how much analyzable DNA would you say, 25 to 50 nanograms?

# 85 A:

About 25 nanograms is what Robin Cotton estimated.

# 86 Q:

Right. She wouldn't have been able to get an RFLP result unless she had about 25 nanograms to analyze with DNA?

# 87 A:

That's correct. That's what I'm saying. It's right on the borderline of what you need to get a result.

# 88 Q:

She did get a result. You're not challenging her result, correct?

# 89 A:

No. I'm saying that that result, because it is on the borderline of RFLP, you're now in the realm of where there's a risk of cross-contamination also showing up on an RFLP type of test.

# 90 Q:

25 nanograms?

# 91 A:

Correct.

# 92 Q:

At the very same time, as a matter of fact, right before Collin Yamauchi handled that evidence item 52, we've just seen how he handled control for 52, correct?

# 93 A:

Yes.

# 94 Q:

And in order to contaminate the control for 52, if he got on as little as point 1 nanograms of DNA, it would have registered on the PCR test, correct?

# 95 A:

I'm not sure I'd go as low as point 1, but much smaller amount, certainly one or around there.

# 96 Q:

So something on the order of 100 times less DNA would have shown up on the PCR test if the control item was contaminated, and would have had to have contaminated the evidence item in order to get an RFLP test?

# 97 A:

It should have shown up.

# 98 Q:

Right. Not very likely, is it, Doctor?

# 99 A:

Again, these controls don't always come up. And so there are things -- other explanations that are theoretical explanations to explain that. But it should have come up.

# 100 Q:

The control was tested right, then, by Collin, and it didn't show anything at all, did it?

Now. Let's go back just briefly to Mr. Yamauchi's work on those two days.

# 101 MR. LAMBERT:

Let's mark this as the next in order.

# 102 THE CLERK:

2265.

# 103 (The instrument herein referred to as list of items - 6/14/94 and 6/15/94 was marked for identification as Plaintiffs' Exhibit No. 2265.)

# 104 MR. LAMBERT:

I'll give you a copy, too. Easier to see.

# 105 (Counsel hands Plaintiffs' Exhibit 2265 to witness.)

# 106 Q:

Now, Dr. Gerdes, this is a list of the two different runs done by Collin Yamauchi on 6/14 and 6/15. We've listed the evidence items tested. The exemplar you did, one exemplar that day for Mr. Simpson, and all other controls.

And you will agree that Collin Yamauchi, when he did those sample tests that day, employed all of those controls, correct?

# 107 A:

Yes.

# 108 Q:

And let's see. The next day -- then the next day he had 19 things, 19 samples tested. And again, we see all the controls that were used by him when he ran those two tests, right?

# 109 A:

Yes.

# 110 Q:

Okay. Let's see the bottom.

So between the two days, 42 evidence -- 42 samples were run through the process, 21 of them evidence samples, and 21 of them controls, correct?

# 111 A:

I'd have to add it up quickly.

I'll I take your word for it.

# 112 Q:

And will you take my word for it that, therefore, 50 percent of the samples that went through the process were actually controls? Right, Doctor?

# 113 A:

Yes.

# 114 Q:

And every single one of them was negative for DNA, correct?

KEY QUOTE

# 115 A:

That's correct.

# 116 MR. LAMBERT:

I have no further questions.

REDIRECT EXAMINATION BY MR. BLASIER:

Temperature

tense

Key Quotes (4)

Tom Lambert

And every single one of them was negative for DNA, correct?

Lambert emphasized that all 21 controls were negative for DNA, and Gerdes agreed, while having earlier qualified that controls do not always reveal contamination.

John C. Gerdes

There's no direct evidence of that.

Gerdes concedes that he had no direct evidence that LAPD caused contamination.

John C. Gerdes

Yes, it is.

Gerdes agrees that the 11-probe and 5-probe RFLP match showing Nicole Brown Simpson's blood on the socks is 'extremely probative' — a significant concession given his role as a defense expert.

Tom Lambert

-- of all of the RFLP results, the only one that you have any quarrel with at all is item 52?

Gerdes agrees that Item 52 is the only RFLP result he challenges, while maintaining his separate position that wrist-area PCR matches might have resulted from contamination.

Evidence (5)

Plaintiffs' 293

Bronco DNA results board

displayed, discussed — Gerdes concedes the displayed RFLP results were not caused by contamination except for the low-quantity result later identified as Item 52

Plaintiffs' 320

DNA analysis results board for the glove

displayed, discussed — Gerdes concedes RFLP results not caused by contamination; maintains only wrist-area PCR results are potentially contaminated

Plaintiffs' 299

DNA results board for socks found at Rockingham

displayed, discussed — Gerdes agrees the 11-probe/5-probe Nicole Brown Simpson match was extremely probative and the 9-probe Mr. Simpson match was very significant

Plaintiffs' 2265

List of items processed by Collin Yamauchi on 6/14/94 and 6/15/94, including evidence samples and all controls

marked for identification during cross and handed to the witness — used to establish that 21 of 42 samples were controls, all of which tested negative

Informal

Item 52 — one of five Bundy blood drops; the only RFLP result Gerdes challenged as potentially contaminated

discussed at length; Gerdes argues borderline DNA quantity (~25 nanograms) creates contamination risk

Notable Exchanges (3)

Tom Lambert•John C. Gerdes

Lambert walks Gerdes through the RFLP result boards; Gerdes agrees that Item 52 is his only RFLP quarrel, while maintaining that PCR matches at the glove wrist might have resulted from contamination.

strategic

Tom Lambert•John C. Gerdes

Lambert suggests that contamination at the glove wrist would likely have affected other glove areas or the adjacent control swatch. Gerdes responds that other areas may have contained more competing DNA and agrees that contamination elsewhere was a possibility.

revealing

Tom Lambert•John C. Gerdes

On Item 52 contamination, Lambert proposes that 0.1 nanograms would register on PCR and that an amount 100 times smaller would therefore appear in the control. Gerdes declines the 0.1-nanogram threshold, says approximately one nanogram or a similarly much smaller amount, and agrees contamination should have shown up while noting that controls do not always do so.

devastating

Light Moments (1)

Hiroshi Fujisaki

Judge Fujisaki announces to the courtroom that the chambers shown (presumably on a monitor or in footage) are not his — 'I'm borrowing that chambers. And all the art work and everything, except for — Are not mine.'

Credibility Attacks (2)

⚔ John C. Gerdes

logical entrapment / concession extraction

Lambert systematically forces Gerdes to concede that every RFLP result across the Bronco, glove, and socks evidence is valid and not caused by contamination, leaving only a single borderline item (Item 52) as a target — and then undermining that with the clean control data.

⚔ John C. Gerdes

admission of no direct evidence

Gerdes said there was no direct evidence that LAPD did anything to cause contamination.

Objections

3 objections (0 sustained, 3 overruled)

Proceeding 8629 • 116 lines • Defense witness

Civil Trial

Department 103