📄 Sidebar: validation study documents — Friday, May 26, 1995
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TRIAL
▲ Day 83 of 167

Sidebar: validation study documents

Date: Friday, May 26, 1995 • Utterances: 12
During a sidebar, Barry Scheck sought to use LAPD PCR validation study documents — produced in early discovery — to confront criminalist Colin Yamauchi with apparent discrepancies between his reported typing results and the expected results in mock vaginal swab tests. Rockne Harmon objected that the documents lacked foundation and were essentially being used as unvetted hearsay confrontation. Judge Ito acknowledged a foundational problem but told Scheck he could proceed if he could lay proper foundation through the witness.
1 THE COURT:

All right. Mr. Scheck, if you recollect, there's a Court order directing all parties to display their documents so we don't have to stand around and do this again. So both sides are reminded of that. All right. What's the problem with this?

2 MR. HARMON:

Well, this--can I speak? I made the objection. This would seem to relate to the whole Gerdes thing. They said they have one question about it, and I have accepted that. I had meant to bring that up again before we started. But it can go on and on.

3 THE COURT:

All these things are validation studies, Mr. Scheck?

4 MR. SCHECK:

Yes, your Honor. They have nothing to do with Dr. Gerdes. If I can explain to the Court--

5 THE COURT:

All right.

6 MR. SCHECK:

--what these were. What this is is the PCR validation study that was turned over to us in discovery before we even had the jury. So what this is is a report from LAPD, the very first discovery we got indicating that the validation work performed by criminalists Reilly and Yamauchi and that every sample gave the expected typing result or no typeable result was observed, at no time was there incorrect typing observed. They then produced for us a code indicating mock vaginal swabs where they simply list here what the expected types are for each of these different samples. Then they produced for us in the same batch the hybridization validation studies. And this had nothing to do with Mark Taylor going to the lab and looking at those books. They produced this in the first round and this has nothing to do with reading strips. This has to do with their readings. When one reviews what Mr. Yamauchi reported as the typing results and compares it to the code, which I did myself, you can see that he got two different answers. So has nothing to do with the reading strip. It has to do what he reports his results are. It's not a contamination issue. It's just a mistake.

7 MR. HARMON:

Somebody else graded them and said he got the right answer? I'm not sure I follow that. How do you get--

8 MR. SCHECK:

Well, he'll explain it. But all I can do from my discovery is go through this. I have a listing of one to 11 mock vaginal swabs and we have typing of one to 11, and what we can see is that there are two mistakes. And this is the only such document I'm going to go into. But this has nothing to do with Dr. Gerdes. This has to do with their discovery and what their reported results are.

9 THE COURT:

How do you know these are the same things?

10 MR. SCHECK:

Well, he can tell us if they're not. If I'm--you know--when one looks at the--compares the typing results with the other samples, they all correspond except for certain ones. Maybe he can explain it. This is a document they gave us.

11 MR. HARMON:

"This is a document they gave us," that's a nice--that hasn't been incorporated into California evidence code as a hearsay objection or exception. So he wants to show him pieces of paper that he hasn't produced and confront him with--we see the problem. This is September `93. Had there been a question, your Honor, these guys have open access to Greg Matheson all along. But they just want to confront him with a piece of paper they say, "Well, this is what we got in discovery." So there's a problem here, right? And I just don't think they have made an offer of proof. And given that date on it, it sure seems like it's irrelevant.

12 THE COURT:

Well, you have a foundational problem at this point with these documents. But if you can lay a foundation and if he says the right thing, you get all the right answers, these are appropriate documents--you've got to ask the questions.

KEY QUOTE

Temperature

procedural

Key Quotes (4)

Barry Scheck
When one reviews what Mr. Yamauchi reported as the typing results and compares it to the code, which I did myself, you can see that he got two different answers.
Scheck's core claim: Yamauchi made at least two errors in his PCR typing results, documented in the prosecution's own discovery materials.
Barry Scheck
It's not a contamination issue. It's just a mistake.
Scheck carefully distinguishes this line of attack from the broader Gerdes contamination theory — framing it as simple error by Yamauchi, not systemic lab problems.
Rockne Harmon
'This is a document they gave us,' that's a nice--that hasn't been incorporated into California evidence code as a hearsay objection or exception.
Harmon sarcastically punctures Scheck's implicit argument that discovery production alone authenticates a document for trial use.
Lance A. Ito
Well, you have a foundational problem at this point with these documents. But if you can lay a foundation and if he says the right thing, you get all the right answers, these are appropriate documents--you've got to ask the questions.
Ito's ruling: documents not blocked outright, but Scheck must establish foundation through Yamauchi's testimony before using them.

Evidence (2)

Informal
LAPD PCR validation study — first discovery batch, reporting criminalists Reilly and Yamauchi's typing results on mock vaginal swabs (samples 1–11), including expected result codes
Scheck sought to use to impeach Yamauchi; Ito conditioned use on proper foundation
Informal
Hybridization validation studies produced in same first discovery batch
Referenced by Scheck as part of the same document set

Notable Exchanges (2)

Barry ScheckRockne Harmon
Harmon pushed back that Scheck had open access to Greg Matheson throughout the trial and could have raised questions earlier, framing the last-minute document confrontation as a procedural ambush rather than legitimate impeachment.
strategic
Barry ScheckLance A. Ito
Ito reminded Scheck of the standing court order requiring parties to display documents in advance, suggesting this sidebar was partly caused by Scheck's non-compliance with prior procedure.
admonishing

Credibility Attacks (1)

⚔ Colin Yamauchi
Prior inconsistent results — internal document comparison
Scheck argued that comparing Yamauchi's reported PCR typing results against the expected-result code in LAPD's own validation study revealed two discrepancies, suggesting Yamauchi made errors in his lab work independent of any contamination issue.

Objections

1 objections (0 sustained, 0 overruled)
Proceeding 6204 • 12 utterances
Criminal Trial
Department 103
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📂 MAY 26, 1995 📄 Sidebar: validation study docu
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