📄 Direct examination of Dr. Robin Cotton (afternoon, part 4) — Wednesday, May 10, 1995
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▲ Day 71 of 167

Direct examination of Dr. Robin Cotton (afternoon, part 4)

Witness: Dr. Robin Cotton
Examiner: George Clarke
Called by: Prosecution • Date: Wednesday, May 10, 1995 • Utterances: 64
George Clarke conducts direct examination of DNA expert Dr. Robin Cotton about the analysis of item 78, a stain found on Ron Goldman's boot. Dr. Cotton explains that the 11 bands on the autoradiograph indicate DNA from more than one contributor — the dominant pattern is consistent with Nicole Brown Simpson, while three fainter bands are consistent with Goldman himself. She declines to make a definitive conclusion about Goldman's contribution from this film alone, stating it is 'inconclusive.'
1 MR. CLARKE:

Now, first of all, Dr. Cotton, are these the same films that you've just looked at and testified about with regard to the Bundy stain as well as the foyer stain?

2 DR. COTTON:

Yes.

3 MR. CLARKE:

Now, what would I'd like to do is focus your attention in particular to what's labeled item no. 78, the stain from Mr. Goldman's boot.

4 DR. COTTON:

Yes.

5 MR. CLARKE:

First of all, is this the--what you referred to earlier as the cocktail film or cocktail x-ray?

6 DR. COTTON:

Yes, it is.

7 THE COURT:

All right. This is 257-A, correct?

8 MR. CLARKE:

Yes.

9 MR. CLARKE:

As far as banding patterns that are present for the boot, can you tell us about them? What do you see?

10 DR. COTTON:

There are quite a few bands in this pattern, and I count one, two, three, four, five, six, seven, eight, nine, ten, eleven.

11 MR. CLARKE:

When you see 11 bands as you've just counted them, does that have any particular meaning to you as a DNA analyst?

12 DR. COTTON:

Yes.

13 MR. CLARKE:

What?

14 DR. COTTON:

If we have two bands--this is--four probes went into this cocktail. If we have two bands with each probe, if we only had one person, the maximum number of bands we could have would be eight. The fact that we have 11 bands here means that we have more than one person here, and it generally--I would conclude that we have two. I certainly wouldn't conclude that we have three.

15 MR. CLARKE:

With regard to these bands, are there any other opinions you can offer, not just from the number of bands, but from also what appears to be differences in how dark the bands are?

16 DR. COTTON:

The bands that are the first--the first eight, these ones at the top, are all very easy to see. They are pretty intense. They're not all identical, but they're pretty intense. The three lower bands, this one, this one and this one (Indicating) are much lighter. And from that, I would make a preliminary conclusion that I had one person there who had a--where there was a fair amount of DNA from that person and a second person who is only represented or who is represented by a much smaller amount of DNA.

17 MR. CLARKE:

Is the darkness of the bands themselves some indication of the relative amounts of DNA present?

18 DR. COTTON:

As I've said earlier, that's the most useful and easiest way to think about bands being darker and lighter. There are a lot of technical things that can go into bands being darker and lighter. But of all the reasons why a band would be darker or lighter than another, the primary one is going to be how much DNA is present, and then there will be a whole series of secondary things that can affect the intensity as well.

19 MR. CLARKE:

Following your review of the banding patterns for the boot stain, did you reach any preliminary or other conclusions about which if any of the three persons, Mr. Simpson, Nicole Brown or Ron Goldman, that could or could not have been donors of the DNA from that boot stain?

20 DR. COTTON:

Yes, we did.

21 MR. CLARKE:

All right. Can you describe those, please?

22 DR. COTTON:

The initial conclusions that we made using just this film alone was that there was a DNA banding pattern, and that is the top eight bands, that is consistent with the DNA banding pattern from Nicole Brown. And I know this is dark on the screen here, but she also has eight bands in similar positions.

KEY QUOTE
23 MR. CLARKE:

All right. If you could, would you mark those locations, but use a different colored arrow.

24 (The witness complies.)
25 MR. CLARKE:

Now, with regard to the three bands that are lighter in intensity--and I'm referring to again the lane with the boot stain on it--and they are the three arrows in pink--are there any other individuals on this particular film that can either be excluded or included as possible donors of those--I'm sorry--of those bands?

26 DR. COTTON:

Mr. Simpson does not have--he has a band down here that may be in about the same position as this one. He has no band in the vicinity where this last band, that is the lowest one in item 78 is (Indicating). So he doesn't seem to be a possible donor to the DNA in item 78. Mr. Goldman has three bands in his pattern, and that's not his whole pattern, but the three lower bands in his pattern seem to be consistent with these three light bands. And I wouldn't want to make any further conclusion about those three light bands other than they're consistent with him. But that's about all you can say.

27 MR. CLARKE:

What about all of those bands in Mr. Goldman's samples that are above the three that you have marked or where the three pink arrows are?

28 DR. COTTON:

Based on this film, we can't tell whether any of those other bands--let me rephrase that. Based on this film, we can't tell whether or not there are any additional bands in item 78 that may or may not be consistent with Mr. Goldman's known sample.

29 MR. CLARKE:

Now, turning your attention to what appears to be the lower or bottom-most band on Mr. Goldman near the bottom of the film.

30 DR. COTTON:

Yes.

31 MR. CLARKE:

Do you see that?

32 DR. COTTON:

I do. You're talking about this one right here (Indicating)?

33 MR. CLARKE:

Yes. Is there any band in that location in the evidence sample itself, the boot stain?

34 DR. COTTON:

I don't recall that there is, but I'd like to look at the original to give you an answer.

35 MR. CLARKE:

All right. Before--

36 THE COURT:

Before--

37 MR. CLARKE:

I was just going to say that. Before you do that, could we have this particular--

38 THE COURT:

All right. Let's move the exemplar arrow off the diagram though, off the autorad.

39 DR. COTTON:

The--

40 THE COURT:

The current arrow, the live arrow, pull it off the diagram.

41 DR. COTTON:

Oh, this one.

42 THE COURT:

Yeah. Pull it off so there's no confusion.

43 (The witness complies.)
44 MR. CLARKE:

And, your Honor, could this be--

45 THE COURT:

This would be 257-A(2).

46 MR. CLARKE:

Very good.

47 THE COURT:

All right. Mr. Fairtlough, do we have that captured?

48 MR. FAIRTLOUGH:

Yes, your Honor.

49 THE COURT:

All right.

50 MR. CLARKE:

Dr. Cotton, showing you the original film, could you look at the light box and see if there are any band in the location on the boot stain in a similar location to Mr. Goldman's lower-most band?

51 DR. COTTON:

I don't see one that I would be happy interpreting. I don't think there is.

52 MR. CLARKE:

Now, does that--does the fact that there's no band that you would be able to interpret from this particular--

53 THE COURT:

Let's--you want to clear the arrows on this?

54 (The witness complies.)
55 MR. CLARKE:

And again, if you could point out, Dr. Cotton, just the location that we're talking about.

56 DR. COTTON:

Can you move it up a little? There we go. All right. You were asking me if there's anything equivalent to this band in Mr. Goldberg over here in item 78. I don't see anything even when I look at the original film that's clearly distinguishable in that area as a band.

57 MR. CLARKE:

As a result of simply this film from this cocktail, are you able to exclude or include Mr. Goldman as a donor of some of the DNA in that boot stain?

58 DR. COTTON:

I really wouldn't want to make any conclusion based on this film alone.

59 MR. CLARKE:

Why not?

60 DR. COTTON:

It's not enough information.

61 MR. CLARKE:

And when you say "not enough information," what do you mean?

62 DR. COTTON:

What I mean is, there are three additional bands in item no. 78. They appear to be consistent with three of the bands from Mr. Goldman's pattern, but apart from that statement, it doesn't mean that it is his. From this film, you can't say that they match his. In terms of his whole pattern, you can't say he's--that Mr. Goldman is definitely a contributor to item no. 78. On the other hand, you can't say he's definitely not a contributor to item no. 78. So basically from this film, you are making an inconclusive statement. I don't know is the bottom line regarding Mr. Goldberg.

63 MR. CLARKE:

And would you want further information if you were able to obtain further information to make such a conclusion?

64 DR. COTTON:

Yes.

Temperature

procedural

Key Quotes (4)

Dr. Robin Cotton
The fact that we have 11 bands here means that we have more than one person here, and it generally--I would conclude that we have two. I certainly wouldn't conclude that we have three.
Establishes that the boot stain is a mixed DNA sample from at least two contributors, a foundational point for the prosecution's theory.
Dr. Robin Cotton
The initial conclusions that we made using just this film alone was that there was a DNA banding pattern, and that is the top eight bands, that is consistent with the DNA banding pattern from Nicole Brown.
Places Nicole Brown Simpson's DNA on Ron Goldman's boot, central to the prosecution's crime scene narrative.
Dr. Robin Cotton
I don't know is the bottom line regarding Mr. Goldberg.
Candid admission that the film alone cannot confirm or exclude Goldman as a contributor to his own boot stain — and she accidentally calls him 'Goldberg,' a notable slip.
Dr. Robin Cotton
From this film, you can't say that they match his. In terms of his whole pattern, you can't say he's--that Mr. Goldman is definitely a contributor to item no. 78. On the other hand, you can't say he's definitely not a contributor to item no. 78.
Demonstrates the limits of single-film DNA analysis and sets up the need for additional testing.

Evidence (4)

People's 257-A
Cocktail autoradiograph (x-ray film) showing DNA banding patterns for item 78 (boot stain) and known reference samples from Simpson, Nicole Brown, and Goldman
discussed and annotated with arrows by witness on screen
People's 257-A(2)
Captured screenshot of the annotated autoradiograph with witness's arrows marking band positions
captured by court technician Fairtlough during testimony
Informal
Item 78 — stain from Ron Goldman's boot
discussed as the primary evidence sample under analysis
Informal
Original autoradiograph film reviewed on light box
examined by witness to confirm presence or absence of specific bands

Notable Exchanges (2)

Lance A. ItoDr. Robin Cotton
Judge Ito intervenes multiple times to manage the arrow annotations on the displayed autoradiograph, instructing the witness to pull the live arrow off the diagram to avoid confusion before capturing screenshots for the record.
procedural
George ClarkeDr. Robin Cotton
Clarke presses Cotton on whether Goldman can be included or excluded as a donor; Cotton carefully declines to reach any conclusion from the single film, explaining the three lighter bands are merely 'consistent' — not a match — and that the lower-most Goldman band has no counterpart in the boot stain.
strategic

Light Moments (1)

Dr. Robin Cotton
Dr. Cotton twice refers to Ron Goldman as 'Mr. Goldberg' — once mid-explanation and once in her concluding 'I don't know' statement — without apparent notice or correction from counsel.

Witness Demeanor

(The witness complies.) — marks arrows on the autoradiograph display as directed
(The witness complies.) — removes arrow from diagram per Judge Ito's instruction
(The witness complies.) — clears arrows from second display
Witness steps to light box to examine original film directly before answering Clarke's question about the lower-most Goldman band

Objections

None recorded
Proceeding 6001 • 64 utterances • Prosecution witness
Criminal Trial
Department 103
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📂 MAY 10, 1995 📄 Direct examination of Dr. Robi
MAY 10, 1995 KRT DvH TD