ProsecutionMilwaukee County District Attorney's Office

Norman A. Gahn

Milwaukee County assistant district attorney and a special prosecutor in the Avery and Dassey cases.

2,021 lines·42 proceedings·1 mention·2 trials

About

Norman A. Gahn was a special prosecutor in Steven Avery's 2007 trial and examined forensic witnesses about DNA, bloodstains, skull fragments, and EDTA testing. After the defense challenged a bullet DNA result because DNA appeared in a test control, he asked the analyst to distinguish contamination of the control from contamination of the evidence sample. He sought an opinion linking Avery's photographed hand cut to a dashboard stain, but the judge sustained the defense's objection. On the disputed source of RAV4 bloodstains, Gahn presented an FBI analyst's opinion that three tested stains did not come from Avery's preserved blood tube and questioned a defense expert about the limits of her contrary criticism; the court allowed the FBI analyst's opinions.

In Brendan Dassey's trial, Gahn examined analysts about DNA findings and their detection limits, including why a negative test did not establish whether someone had been at a scene. He also examined a blood-pattern analyst about RAV4 cargo-area stains and the limits of interpreting them, challenged defense testimony concerning a phone-call time and the absence of fingerprints, and opposed a renewed motion to dismiss amended Count 3. The court denied that motion, finding sufficient corroboration of Dassey's confession.

Trial Record (42)

AverySteven AveryFeb 12, 2007 – Mar 18, 2007

Norman A. Gahn, a special prosecutor in Steven Avery's 2007 trial, led forensic examinations on RAV4 bloodstains, DNA evidence, skull fragments, and EDTA testing. He defended the contested bullet DNA result and questioned a defense expert about the limits of her criticism of the FBI's blood testing.

Day 10

Feb 23, 2007

DirectRonald L. Groffy — DirectRonald L. GroffyNorman A. Gahn58lines spoken

Summary

Groffy identified vehicle photographs and reported positive presumptive blood tests on two areas of the RAV4.

CrossRonald L. Groffy — CrossRonald L. GroffyJerome F. Buting4lines spoken

Summary

Groffy described limits on his RAV4 testing, clarified photograph timing and fingerprint markings, and testified about the driver's-seat fit. The court admitted the vehicle photographs.

DirectSherry Culhane — DirectSherry CulhaneNorman A. Gahn508lines spoken

Summary

Culhane presented DNA comparisons from the RAV4, charred remains, bullet fragment, hood latch, and key, and disclosed contamination in a bullet-test negative control.

ProceduralEnd-of-day jury admonition after Culhane’s direct examination4lines spoken

Summary

The court gave jurors weekend instructions, then admitted forensic exhibits and reviewed outstanding exhibit status. The defense reserved its position on whether five Crime Lab reports should go to the jury during deliberations.

Day 11

Feb 26, 2007

CrossSherry Culhane — CrossSherry CulhaneJerome F. Buting26lines spoken

Summary

Buting challenged the limits of Culhane's DNA conclusions and her bullet-fragment result, focusing on a contaminated control, a protocol deviation, and its omission from her final report.

RedirectSherry Culhane — RedirectSherry CulhaneNorman A. Gahn69lines spoken

Summary

Culhane defended her bullet DNA conclusion despite contamination in the test control, explained her protocol deviation, and identified a buccal-swab envelope that the court kept closed pending recross.

ProceduralBuccal-swab envelope hearing: chain of custody and planting-theory dispute1highlight8lines spoken

Summary

Counsel disputed the buccal-swab envelope's seal and the scope of the defense's planting theory; the judge set a procedure for showing and describing the envelope before opening it.

Highlights (1)

confrontationGahn argued that the defense was extending its planting theory beyond its earlier offer of proof. Buting answered that Culhane's testimony about a possible non-blood DNA source warranted exploring other sources.Open in transcript →

RedirectSherry Culhane — Redirect ContinuedSherry CulhaneNorman A. Gahn1highlight21lines spoken

Summary

Culhane described the opened package's swab kit and testified that the inner envelope's seals appeared unbroken, while saying its markings did not show when she resealed it.

Highlights (1)

evidence eventAfter Buting had Culhane describe the outer tape, he asked that the thin Scotch tape be peeled back before the package was cut. Gahn did not object, and the court directed Culhane to proceed once both sides agreed.Open in transcript →

RecrossSherry Culhane — RecrossSherry CulhaneJerome F. Buting5lines spoken

Summary

Culhane agreed that without a protocol-permitted deviation, the bullet DNA result would have been reported as inconclusive; she maintained that her DNA contaminated the control, not the evidence extract.

RedirectSherry Culhane — Further RedirectSherry CulhaneNorman A. Gahn1highlight5lines spoken

Summary

Culhane defended the bullet-test protocol deviation, saying her DNA was in the control, not the evidence sample.

Highlights (1)

objectionThe judge sustained Buting's asked-and-answered objection to Gahn's follow-up question about the control result's effect on the bullet conclusion.Open in transcript →

DirectNick Stahlke — DirectNick StahlkeNorman A. Gahn65lines spoken

Summary

Stahlke described photographed stains inside the RAV4; a proposed link between a hand cut and a dashboard stain drew foundation and disclosure objections.

ProceduralHearing on scope and disclosure of Stahlke’s bloodstain opinion6lines spoken

Summary

The judge sustained the defense's objection to a proposed bloodstain opinion linking a photographed cut to a dashboard stain.

DirectNick Stahlke — Direct ContinuedNick StahlkeNorman A. Gahn67lines spoken

Summary

Stahlke interpreted RAV4 cargo-area and rear-door bloodstains, described disconnected battery cables, and compared stains in two vehicles; the judge then required notice of further frame-up evidence.

Day 12

Feb 27, 2007

ProceduralRenewed Motion to Suppress Bullet Fragment FL Test ResultsMentioned1line spoken

Summary

The defense renewed its motion to suppress the bullet fragment FL test results; the court took it under advisement and allowed the State time to respond.

Mentioned in this proceeding.

Day 15

Mar 2, 2007

DirectJeffrey Jentzen — DirectJeffrey JentzenNorman A. Gahn60lines spoken

Summary

Jeffrey Jentzen interpreted two skull fragments and their x-rays as consistent with entrance gunshot wounds and gave his opinion on Teresa Halbach's cause and manner of death.

CrossJeffrey Jentzen — CrossJeffrey JentzenDean A. Strang2lines spoken

Summary

Jentzen conceded he could not tell whether the skull wounds occurred before or after death, but maintained his gunshot cause-of-death and homicide manner-of-death opinions.

RedirectJeffrey Jentzen — RedirectJeffrey JentzenNorman A. Gahn1highlight12lines spoken

Summary

Jentzen explained his method and reaffirmed his gunshot-wound and homicide opinions; the judge clarified the jury's role after an objection.

Highlights (1)

evidence eventAt Gahn's request and without objection, the court admitted Exhibit 432, Jentzen's CV.Open in transcript →

Day 16

Mar 5, 2007

DirectMarc LeBeau — DirectMarc LeBeauNorman A. Gahn146lines spoken

Summary

Marc LeBeau testified that FBI testing found EDTA in Steven Avery's purple-topped blood tube but not in three bloodstain swabs from Teresa Halbach's RAV4. He opined that the tested stains did not come from that tube.

CrossMarc LeBeau — CrossMarc LeBeauJerome F. Buting15lines spoken

Summary

Buting challenged the FBI's case-specific EDTA test, including its blind-testing practices, detection limits, and stability assumptions. LeBeau defended the method but agreed that nondetection does not establish an absolute absence of EDTA.

ProceduralPost-testimony EDTA motion proceedings6lines spoken

Summary

The court allowed Dr. LeBeau's EDTA opinions, admitted the day's exhibits, and denied the defense requests for reconsideration and sequential independent testing.

Day 17

Mar 6, 2007

ProceduralDefense motion to preserve blood evidence11lines spoken

Summary

The court invited a proposed order preserving RAV4 blood evidence and a blood vial, while leaving preservation details for later.

DirectMarc LeBeau — DirectMarc LeBeauNorman A. Gahn202lines spoken

Summary

LeBeau testified that EDTA was detected in the submitted blood tube but not in tested RAV4 swabs, and opined that the stains could not have come from that tube. The court rejected a broader planting question.

CrossMarc LeBeau — CrossMarc LeBeauJerome F. Buting12lines spoken

Summary

Buting pressed LeBeau on the FBI's case-specific EDTA method, a later spot-card study, and the reach of his blood-source opinion. LeBeau defended the testing but did not rule out planting from a source without EDTA.

RedirectMarc LeBeau — RedirectMarc LeBeauNorman A. Gahn8lines spoken

Summary

LeBeau explained later trace findings and disclosures concerning his Sybers-case testing, then testified that Dr. Sybers pleaded guilty.

ProceduralRecross interruption and Exhibit 466 dispute4lines spoken

Day 19

Mar 8, 2007

ProceduralRenewed fair-forensic-testing motion1highlight12lines spoken

Summary

The defense sought suppression of Item FL bullet DNA evidence or a jury instruction; the State opposed, and the court reserved its ruling.

Highlights (1)

procedural actionGahn opposed suppression, citing the governing destruction-of-evidence standard and arguing that the bullet and extract tube remained available for possible defense testing.Open in transcript →

DirectLisa Buchner — DirectLisa BuchnerDean A. Strang3lines spoken

Summary

Bus driver Lisa Buchner recalled seeing a woman photograph a van near the Dassey boys' drop-off, but could not recall the exact day.

CrossLisa Buchner — CrossLisa BuchnerNorman A. Gahn55lines spoken

Summary

Buchner could not date her sighting to the week of October 31, but mapped where she recalled seeing a woman and vehicles near her bus drop-off.

ProceduralHearing on proposed Kakatsch testimony9lines spoken

Summary

After a defense offer of proof, the court excluded proposed testimony from Ms. Kakatsch as minimally probative and potentially confusing.

Day 20

Mar 9, 2007

DirectJanine Arvizu — DirectJanine ArvizuJerome F. Buting3lines spoken

Summary

Defense expert Janine Arvizu testified that the FBI’s EDTA non-detections did not rule out EDTA in the tested RAV4 bloodstains, citing an unestablished method detection limit and a two-microliter sample called not detected.

CrossJanine Arvizu — CrossJanine ArvizuNorman A. Gahn1highlight151lines spoken

Summary

Arvizu confirmed EDTA non-detections in three RAV4 bloodstains and positives in blood-tube samples, but maintained that the FBI's instrument detection limit did not establish what its method could detect in a stain.

Highlights (1)

confrontationWhen Gahn used the RAV4 swab photograph to revisit the claimed one-microliter detection threshold, Arvizu said the deposited blood volume was unknown and that she did not believe the data supported a general one-microliter conclusion.Open in transcript →

RecrossJanine Arvizu — RecrossJanine ArvizuNorman A. Gahn8lines spoken

Summary

Arvizu said the blood tube's expiration date did not establish EDTA breakdown and agreed that its EDTA was still acting as an anticoagulant.

Day 21

Mar 12, 2007

ProceduralIndividual seated-juror inquiries about publicity and outside contact3lines spoken

Summary

The court questioned seated jurors about publicity and outside contact, followed up on family comments and television tickers, and recessed without ruling on juror service.

DasseyBrendan DasseyApr 16, 2007 – Apr 25, 2007

Norman A. Gahn examined DNA and blood-pattern experts for the prosecution in Brendan Dassey's 2007 trial, then challenged defense testimony about a phone call and fingerprint evidence. He also opposed a renewed motion to dismiss amended Count 3, which the court denied after finding sufficient corroboration of Dassey's confession.

Day 3

Apr 18, 2007

DirectSherry Culhane — DirectSherry CulhaneNorman A. Gahn244lines spoken

Summary

DNA analyst Sherry Culhane attributed DNA from several RAV4 items and a key to Steven Avery, and DNA from the cargo area, a Pepsi can, and a bullet fragment to Teresa Halbach; she limited her conclusion about charred tissue to a partial-profile comparison.

RedirectSherry Culhane — RedirectSherry CulhaneNorman A. Gahn49lines spoken

Summary

Culhane explained limits of DNA testing, confirmed she found no blood on Brendan Dassey's jeans, and said absent detectable DNA does not establish whether someone was at a crime scene.

DirectNick Stahlke — DirectNick StahlkeNorman A. Gahn84lines spoken

Summary

Nick Stahlke interpreted RAV4 bloodstains as consistent with an actively bleeding person in the passenger area and a possible loading of a body with bloody head hair into the cargo area.

RedirectNick Stahlke — RedirectNick StahlkeNorman A. Gahn9lines spoken

Summary

Stahlke clarified limits of the RAV4 bloodstains and discussed factors that could affect visible blood or later detection.

DirectSusan Brandt — DirectSusan BrandtThomas J. Fallon1line spoken

Summary

Susan Brandt recounted what Kayla Avery told school counselors about a cousin being asked to help move a body, while noting Kayla did not identify the cousin.

Day 6

Apr 21, 2007

CrossMichael Kornely — CrossMichael KornelyNorman A. Gahn15lines spoken

Summary

Kornely could not verify his October 31 call time from his Sprint record and agreed the call might have been as early as 5:15 p.m.

Day 7

Apr 23, 2007

CrossMichael Riddle — CrossMichael RiddleNorman A. Gahn28lines spoken

Summary

Riddle explained why shell casings may yield no comparable prints and agreed that finding no Steven Avery fingerprints in the RAV4 did not establish his absence.

RecrossMichael Riddle — RecrossMichael RiddleNorman A. Gahn3lines spoken

Summary

Riddle confirmed that fingerprints can be removed from an item; the defense had no more witnesses that afternoon.

Day 9

Apr 25, 2007

ProceduralRenewed motion to dismiss Count 3 and corroboration ruling3lines spoken

Summary

The court denied the renewed motion to dismiss amended Count 3, finding sufficient corroboration of Brendan Dassey's confession.