Recross-examination of Collin Yamauchi (morning)

📄 Recross-examination of Collin Yamauchi (morning) — Wednesday, May 31, 1995

Address:

C:\DEPT103\CRIMINAL\1995\MAY\31\RECROSS-EXAMINATION-OF-COLLIN-.DOC

TRIAL

▲ Day 85 of 167

◀ Redirect examination of Collin Yamauchi (morning, part 2) Recess ▶

Witness: Collin Yamauchi
Examiner: Barry Scheck
Called by: Prosecution • Date: Wednesday, May 31, 1995 • Utterances: 151

Scheck pressed Yamauchi on three fronts: his observation notes on Dr. Henry Lee's glove-changing, his failure to perform slot-blots to detect degradation, and most critically, a mock vaginal swab validation study where Yamauchi reported an incorrect DQ-Alpha genotype (1.2,4 instead of 1.2,1.3 for the sperm fraction) and neither he nor his supervisor flagged it as an error. The examination grew increasingly combative as Harmon objected repeatedly to Scheck's attempts to get Yamauchi to admit the mistaken typing would have constituted a false exclusion in a real case.

# 1 THE COURT:

Mr. Scheck.

RECROSS-EXAMINATION BY MR. SCHECK

# 2 MR. SCHECK:

Mr. Yamauchi, do you believe that Dr. Henry Lee handles evidence in the same fashion that you do at the LAPD laboratory? Is that what you are telling us?

# 3 MR. YAMAUCHI:

Yes, from my observations of him.

# 4 MR. SCHECK:

And in your notes you have a whole series of notations of what Dr. Lee did, correct?

# 5 MR. YAMAUCHI:

Yes.

# 6 MR. SCHECK:

All right. And after each notation do you have "Same gloves"?

# 7 MR. YAMAUCHI:

Yes.

# 8 MR. SCHECK:

Everyone of them?

# 9 MR. YAMAUCHI:

Not everyone of them, but I did write that in at certain points.

# 10 MR. SCHECK:

You write down "Same gloves" at the end?

# 11 MR. YAMAUCHI:

Yes.

# 12 MR. SCHECK:

So basically you wrote down something that after observing the whole observation you didn't recall him changing gloves?

# 13 MR. YAMAUCHI:

That's right.

# 14 MR. SCHECK:

Now, you were asked on redirect examination about slot-blots. Do you recall that?

# 15 MR. YAMAUCHI:

Yes.

# 16 MR. SCHECK:

You were asked about degraded samples?

# 17 MR. YAMAUCHI:

Yes.

# 18 MR. SCHECK:

Now, if one does a slot-blot, that will give you information as to how much human DNA is in the sample?

# 19 MR. YAMAUCHI:

Yeah. It will give you an approximation.

# 20 MR. SCHECK:

And a reading on how much human DNA is in a sample could assist you in making an assessment as to whether or not you are dealing with degraded samples?

# 21 MR. YAMAUCHI:

To a certain extent it could, yes.

# 22 MR. SCHECK:

And don't you agree that in terms of guarding against cross-contamination it is important to know if you are dealing with degraded samples?

# 23 MR. YAMAUCHI:

Not if you are following procedure to make sure that everything is done at a separate time.

# 24 MR. SCHECK:

You did not perform a slot-blot in this case, did you?

# 25 MR. YAMAUCHI:

No, I didn't.

# 26

MR. SCHECK: Now--(Discussion held off the record between Deputy District Attorney and Defense counsel.)

# 27 MR. SCHECK:

Now, Mr. Harmon asked you some questions about the LAPD mock vaginal swab exercise. Yes?

# 28 MR. YAMAUCHI:

Yes.

# 29 MR. SCHECK:

Now, to your knowledge did anyone else in your laboratory perform the mock vaginal swab exercise?

# 30 MR. HARMON:

Objection, it is irrelevant, beyond the scope, calls for hearsay.

# 31 THE COURT:

Overruled. Overruled.

# 32 MR. YAMAUCHI:

They might have.

# 33 MR. SCHECK:

Well, wasn't there a standard given out to others in your lab?

# 34 MR. YAMAUCHI:

Well, it was made available.

# 35 MR. SCHECK:

And do you know if anyone else in your laboratory, with respect to sample no. 1, got the 1.2, 1.3 result for the sperm sample?

# 36 MR. YAMAUCHI:

I'm not sure and I'm not sure they would have examined the same swabs that I did, because a number of swabs were made up with those types on them.

# 37 MR. SCHECK:

Will you put--

# 38 (Discussion held off the record between Defense counsel.)

# 39 MR. SCHECK:

Now, the way this exercise worked is that vaginal swabs were prepared; is that correct?

# 40 MR. YAMAUCHI:

Yes.

# 41 MR. SCHECK:

And when you were taking the tests, were you supposed to know what the types for the sperm sample and the epithelial fraction of these vaginal swabs was?

# 42 MR. YAMAUCHI:

Well, like I was saying before, it wasn't necessarily a test as much as to see if we can type and get what answers that we expect.

# 43 MR. SCHECK:

My question--

# 44 MR. YAMAUCHI:

And I made those swabs. I made quite a few of these swabs.

# 45 MR. SCHECK:

So when you were taking this test did you know ahead of time what you were supposed to find for each of the different vaginal swabs you were examining?

# 46 MR. YAMAUCHI:

Well, I suppose I could have looked it up, because like I said, I set it up and made it.

# 47 MR. SCHECK:

But my question to you, sir, is when you were doing the typings did you know, for example, no. 1, what result you were supposed to get for the sperm sample?

# 48 MR. YAMAUCHI:

Well, I made them. Of course I would have known.

KEY QUOTE

# 49 MR. SCHECK:

Did you--when you did the typing, did you know?

# 50 MR. YAMAUCHI:

I'm sorry, I'm not understanding you. I made the swabs.

# 51 MR. SCHECK:

I know you made--

# 52 MR. YAMAUCHI:

I would know the types that are on there.

# 53 MR. SCHECK:

My question to you is when you did the typing--could you move that up a little bit. When you did the typing on sample no. 1 on September 9th, 1993, did you have it in mind what you were supposed to get for the sperm fraction as indicated in 2 14-6?

# 54 MR. YAMAUCHI:

Oh, do you mean did I have it memorized in my head all the type results?

# 55 MR. SCHECK:

Yes.

# 56 MR. YAMAUCHI:

No, no. My memory is not that good.

# 57 MR. SCHECK:

Did you sit there with the code sheet next to you and look at the typing--look at the code sheet as you were reading the strips and putting down the typing result?

# 58 MR. YAMAUCHI:

No.

# 59 MR. SCHECK:

So to that extent you didn't know what the answer was supposed to be or what the expected typing result for the sperm fraction was supposed to be when you did the test, right, on September 3rd, 1993?

# 60 MR. YAMAUCHI:

No.

# 61 MR. SCHECK:

Okay. Now, wasn't the point of this exercise to determine whether or not you could accurately and reliably type a mixture?

# 62 MR. YAMAUCHI:

That was the process and it was to give us some swabs that were challenging enough to test our ability so that we would have a better feel of what it is like to type case work samples.

# 63 MR. SCHECK:

So the point of this validation study was to determine whether or not the analysts could accurately and reliably type a mixture on a vaginal swab?

# 64 MR. YAMAUCHI:

Yes, and that is what I did.

# 65 MR. SCHECK:

Okay. And when you are doing a mixture on a vaginal swab where you have sperm cells and epithelial cells, you can engage in a process of what is known as differential extraction?

# 66 MR. YAMAUCHI:

Yes.

# 67 MR. SCHECK:

And that means that you have one set of detergents that will first remove--burst open the epithelial cells?

# 68 MR. YAMAUCHI:

Well, it--it is more than that. It is a little bit more complicated. There is what are known as enzymes or proteases that are involved in that step.

# 69 MR. SCHECK:

But you put reagents into the tube and that is going to burst open the epithelial cells and remove that DNA and then you proceed to the sperm cells, correct?

# 70 MR. YAMAUCHI:

Right, but in that first process to a certain extent sometimes the sperm could be lysed also.

# 71 MR. SCHECK:

But the point is you have a process available known as a differential extraction which permits you, when you have sperm cells and epithelial cells, to attempt to do them separately, right?

# 72 MR. YAMAUCHI:

To a certain extent, and once again, there is oftentimes spill over from one fraction to the other because the process, it is not perfect.

# 73 MR. SCHECK:

Now, when you are dealing with bloodstain mixture, there is no process available to you to do a differential extraction?

# 74 MR. YAMAUCHI:

Why would you need to? Bloodstains are all the same cell line.

# 75 MR. SCHECK:

If you have a bloodstain that could have been created by mixtures of two or more contributors, one cannot go through a differential extraction process to determine contributors, right?

# 76 MR. YAMAUCHI:

Yes, that's correct.

# 77 MR. SCHECK:

So to that extent there are more tools available to the forensic analyst in terms of sorting out mixtures when you are dealing with epithelial cells and sperm cells?

# 78 MR. YAMAUCHI:

Yes, in that regard.

# 79 MR. SCHECK:

And so would it be fair to say that doing differential extractions on vaginal swabs is easier than sorting out mixtures on bloodstains?

# 80 MR. HARMON:

Objection. That is argumentative, your Honor.

# 81 THE COURT:

Overruled.

# 82 MR. YAMAUCHI:

Personally I don't think it is easier, and I don't think anybody else that analyzes these samples do either.

# 83 MR. SCHECK:

Now, Mr. Yamauchi,--

# 84 THE COURT:

Excuse me, Mr. Scheck. Why don't you finish the thought because we need to take a break.

# 85 MR. SCHECK:

Oh, okay.

# 86 THE COURT:

Go ahead and finish the thought.

# 87 MR. SHAPIRO:

Now, with respect to these typing results, there were other instances on this typing run where there was evidence of carry-over between the vaginal, the epithelial cells and the sperm cells, right?

# 88 MR. HARMON:

Objection, it is beyond the scope. It is irrelevant.

# 89 THE COURT:

How much more do you have with this, Mr. Scheck?

# 90 MR. SCHECK:

Two, three minutes.

# 91 THE COURT:

Proceed.

# 92 MR. SCHECK:

There were other instances where there was carry-over, correct, reputed to be carry-over?

# 93 MR. YAMAUCHI:

Yes.

# 94 MR. SCHECK:

That is to say, you got strong readings that were consistent with the sperm fraction and some weak readings that were consistent with either the epithelial cells or the vaginal or the sperm cells, correct?

# 95 MR. YAMAUCHI:

Correct.

# 96 MR. SCHECK:

But what makes no. 1 different here with respect to line 2 is that you got a reading of 1.2, 4 with no indication of other alleles or contributors, right?

# 97 MR. YAMAUCHI:

Yes, that's correct.

# 98 MR. SCHECK:

And if you were reporting this out in a case where a suspect had a 1.2, 4 genotype for the DQ-Alpha system, you would have reported a match?

# 99 MR. HARMON:

Objection, argumentative, it is irrelevant, beyond the scope, speculation.

# 100 THE COURT:

Rephrase the question. Rephrase the question.

# 101 MR. SCHECK:

All right.

# 102 MR. SCHECK:

Let's go both ways. Let's assume, as in the mock vaginal swab exercise here, that the correct genotype for the sperm donor here for the DQ-Alpha system is 1.2, 3.

# 103 MR. YAMAUCHI:

For the sperm donor?

# 104 MR. SCHECK:

Yes.

# 105 MR. YAMAUCHI:

Okay.

# 106 MR. HARMON:

Objection, your Honor, it is irrelevant, beyond the scope.

# 107 THE COURT:

Overruled.

# 108 MR. SCHECK:

That was the genotype of the sperm donor in this exercise, right?

# 109 MR. YAMAUCHI:

I would have to see the sheet again.

# 110 MR. SCHECK:

All right.

# 111 (Brief pause.)

# 112 MR. SCHECK:

See the sheet? See where it says "SP" at the top?

# 113 MR. YAMAUCHI:

1.2, 1.3.

# 114 MR. SCHECK:

Yes, 1.2, 1.3.

# 115 MR. YAMAUCHI:

Okay.

# 116 MR. SCHECK:

That is what is supposed to be the sperm contribution, correct?

# 117 MR. YAMAUCHI:

Correct.

# 118 MR. SCHECK:

Okay. Now, you reported out a 1.2, 4 on your typing sheet?

# 119 MR. YAMAUCHI:

Right.

# 120 MR. SCHECK:

If this had been a case, that would have been a false exclusion?

# 121 MR. HARMON:

Objection, your Honor. It is argumentative and misstates his testimony and it is irrelevant.

# 122 THE COURT:

Sustained.

# 123 MR. SCHECK:

If you had--if your typing results had been used in a real case instead of a mock case, would that have been an incorrect typing that would have excluded the sperm donor as being a contributor to that vaginal swab?

# 124 MR. HARMON:

Objection, no foundation, speculation. It is argumentative, it is irrelevant.

# 125 THE COURT:

Sustained.

# 126 MR. SCHECK:

Well, the 1.2, 4 is not the correct typing for the sperm contributor, is it?

# 127 (No audible response.)

# 128 MR. HARMON:

Objection, asked and answered.

# 129 THE COURT:

Sustained.

# 130 MR. SCHECK:

The 1.2, 4 typing does not reflect the true genotype of the sperm contributor?

# 131 MR. HARMON:

Objection, asked and answered.

# 132 THE COURT:

Sustained. Counsel, we have been through this.

# 133 MR. SCHECK:

Is there any notation whatsoever on your report, or on any review of this by your supervisor, that there was any incorrect typing reported on this mock vaginal swab exercise by you?

# 134 MR. HARMON:

Objection, asked and answered, beyond the scope.

# 135 THE COURT:

Overruled.

# 136 MR. YAMAUCHI:

I didn't mark down anything being wrong and neither did my supervisor.

KEY QUOTE

# 137 MR. SCHECK:

When you say "Wrong," was the discrepancy even noted?

# 138 MR. YAMAUCHI:

It is not a discrepancy.

KEY QUOTE

# 139 MR. HARMON:

Objection, argumentative.

# 140 THE COURT:

Sustained.

# 141 MR. SCHECK:

Was there any notation put down that the sperm fraction--

# 142 MR. HARMON:

Objection, asked and answered.

# 143 THE COURT:

I haven't heard the question.

# 144 MR. SCHECK:

Was there any notation put down--withdrawn. Other than the report that Collin Yamauchi either got the correct types or no results on all of the validation studies, other than that report, was anything else said about how you did on these mock vaginal swab studies?

# 145 MR. HARMON:

Objection, calls for hearsay.

# 146 MR. SCHECK:

In any document you had in regard to the validation studies--

# 147 MR. HARMON:

Calls for hearsay.

# 148 THE COURT:

Excuse me, counsel. Don't make your objections while the question is being made. It makes it impossible for the court reporter to make an adequate record. You can make your objection at the appropriate time.

# 149 MR. HARMON:

I appreciate counsel doing the same for the first time, your Honor.

KEY QUOTE

# 150 THE COURT:

That wasn't necessary, Mr. Harmon.

KEY QUOTE

# 151 MR. HARMON:

I agree.

Temperature

tense

Key Quotes (5)

Collin Yamauchi

I didn't mark down anything being wrong and neither did my supervisor.

Confirms the incorrect typing in the validation study went uncorrected and unacknowledged — the core of Scheck's attack on lab quality control.

Collin Yamauchi

It is not a discrepancy.

Yamauchi refuses to concede the 1.2,4 result was an error, setting up the clash over whether the lab's quality review was meaningful.

Collin Yamauchi

Well, I made them. Of course I would have known.

Reveals that Yamauchi created the mock swabs himself, undermining the independence of the validation exercise as a blind test of his accuracy.

Lance A. Ito

That wasn't necessary, Mr. Harmon.

Judge reprimands Harmon after a snarky courtroom retort, a rare public rebuke of prosecution counsel.

Rockne Harmon

I appreciate counsel doing the same for the first time, your Honor.

Harmon's sarcastic jab at Scheck (after being told not to interrupt mid-question), which the judge immediately shut down.

Evidence (4)

Informal

Yamauchi's observation notes on Dr. Henry Lee's evidence handling, with 'Same gloves' notations

discussed

Informal

Mock vaginal swab validation exercise — typing sheet showing expected sperm donor genotype 1.2, 1.3 (DQ-Alpha)

discussed, challenged

Informal

Yamauchi's typing report from September 9, 1993 showing 1.2, 4 result for sperm fraction of sample no. 1

challenged as incorrect

2 14-6

Code sheet for mock vaginal swab exercise indicating expected typing results

referenced

Notable Exchanges (3)

Barry Scheck•Collin Yamauchi

Scheck exposed that Yamauchi himself created the mock swabs used in the validation exercise, meaning he was not truly blind to the expected results — undermining the study's value as an independent competency check.

strategic

Barry Scheck•Collin Yamauchi

Scheck repeatedly tried to get Yamauchi to admit the 1.2,4 typing was a false result that would have excluded an innocent person's DNA in a real case. Harmon objected every iteration; most were sustained. Yamauchi never conceded it was 'wrong.'

heated

Lance A. Ito•Rockne Harmon

After Ito told Harmon not to object while questions are being asked, Harmon sarcastically said he appreciated Scheck 'doing the same for the first time.' Ito flatly replied 'That wasn't necessary,' and Harmon said 'I agree.'

tense

Light Moments (1)

Robert Shapiro (misattributed)

Transcript shows 'Robert Shapiro' asking a question mid-examination that is clearly Scheck's question — an apparent court reporter attribution error, briefly breaking the flow.

Credibility Attacks (2)

⚔ Collin Yamauchi

prior inconsistent act / quality control failure

Scheck demonstrated that Yamauchi reported an incorrect DQ-Alpha genotype (1.2,4 instead of 1.2,1.3) in a mock validation study, that he was not truly blind to the expected answers because he created the swabs himself, and that neither he nor his supervisor ever flagged or noted the error — raising questions about whether lab quality review was meaningful.

⚔ Collin Yamauchi

omission / procedure gap

Scheck established that Yamauchi performed no slot-blot in this case, which could have detected degraded samples and informed contamination-prevention decisions.

Witness Demeanor

(No audible response) — Yamauchi went silent when directly asked whether 1.2,4 was the correct typing for the sperm contributor.

(Brief pause) — while Yamauchi reviewed the code sheet to confirm the expected 1.2, 1.3 genotype.

Objections

15 objections (8 sustained, 5 overruled)

Proceeding 6229 • 151 utterances • Prosecution witness

Criminal Trial

Department 103