Expert witnessWisconsin State Crime Laboratory (Madison)

John Ertl

State crime-lab scientist who worked on vehicle, burned-material, and garage-floor evidence.

860 lines·20 proceedings·14 mentions·2 trials

About

John Ertl, a Wisconsin State Crime Laboratory scientist, testified about preserving and transporting Teresa Halbach's RAV4, searching burned material, and testing the garage floor. He described moving the vehicle in an enclosed trailer after weather limited examination at the salvage yard. His accounts of burn-pit work included the absence of a record of each suspected fragment's precise position; he could not identify pieces that looked like teeth or bone as human. A larger garage-floor area reacted to luminol but was not confirmed as blood by phenolphthalein testing, and Ertl could not identify the cause of that reaction. Questioning also established limits on scene coverage, documentation, and what he personally knew.

Trial Record (20)

AverySteven AveryFeb 12, 2007 – Mar 18, 2007Called by prosecution

John Ertl, a state crime-lab scientist, testified in Steven Avery's 2007 trial about the RAV4's transport and searches of the burn pit and other sites. His testimony also set limits on the physical evidence: a faint garage-floor luminol reaction did not yield a phenolphthalein reaction for blood, and the burn-pit collection did not preserve each suspected fragment's precise position.

Day 5

Feb 16, 2007

DirectThomas Fassbender — DirectThomas FassbenderKenneth R. KratzMentioned

Summary

Fassbender outlined the November 5–12 searches, RAV4 handling, and discoveries of a Toyota key, license plates, and bone pieces; a discovery dispute was also raised.

Mentioned in this proceeding.

Day 6

Feb 19, 2007

DirectJohn Ertl — DirectJohn ErtlThomas J. Fallon211lines spoken

Summary

John Ertl traced crime-lab work on the RAV4, burn areas, and nearby search sites, and explained the limits of the garage's luminol result.

CrossJohn Ertl — CrossJohn ErtlJerome F. Buting358lines spoken

Summary

Ertl was pressed on contamination, RAV4 timing, limited scene photography, negative garage-floor blood screening, and how burn pit material was collected.

RedirectJohn Ertl — RedirectJohn ErtlThomas J. Fallon36lines spoken

Summary

Ertl addressed SUV transport, hypothetical key DNA and blood cleanup, and the limits of his bloodstain expertise.

RecrossJohn Ertl — RecrossJohn ErtlJerome F. Buting33lines spoken

Summary

Buting tested Ertl's blood-evidence comparisons and key-DNA hypothetical; Ertl identified limits to his knowledge, and three exhibits were admitted.

Day 10

Feb 23, 2007

ProceduralRenewed search-suppression motion hearingMentioned

Summary

The defense renewed its challenge to searches of Avery's property; the State opposed suppression, and the court deferred a decision pending further burn-pit evidence.

Mentioned in this proceeding.

Day 13

Feb 28, 2007

DirectThomas Sturdivant — DirectThomas SturdivantThomas J. FallonMentioned

Summary

Sturdivant described finding apparent bone fragments near the burn pit, sifting debris with Crime Lab personnel, and preserving the scene; exhibits 363–371 and 373 were admitted.

Mentioned in this proceeding.

CrossThomas Sturdivant — CrossThomas SturdivantDean A. StrangMentioned

Summary

Strang examined Sturdivant about where suspected bone fragments were found and the burn pit recovery's mapping, sifting, and photographic documentation.

Mentioned in this proceeding.

CrossLeslie Eisenberg — CrossLeslie EisenbergDean A. StrangMentioned

Summary

Eisenberg acknowledged limits on dating the skull defects and reconstructing the bone recovery, while confirming human bone in Janda Burn Barrel No. 2.

Mentioned in this proceeding.

Day 19

Mar 8, 2007

ProceduralRenewed challenge to November 5 warrant searchesMentioned

Summary

The defense and State argued over repeated searches under the November 5 warrant, particularly the burn area. The court made no new ruling.

Mentioned in this proceeding.

Day 23

Mar 14, 2007

ClosingState’s Closing Argument by Kenneth KratzKenneth R. KratzMentioned

Summary

Kratz began the State's closing with the RAV4, blood and DNA evidence, and burned electronics; an objection led the court to remind jurors that argument is not fact.

Mentioned in this proceeding.

ClosingState’s Closing Argument ResumesKenneth R. KratzMentioned

Summary

Kratz completed the State's closing by linking its timeline, burn-area, firearm, and DNA arguments and requesting guilty verdicts on the three remaining charges.

Mentioned in this proceeding.

ClosingDefense Closing Argument by Jerome ButingJerome F. ButingMentioned

Summary

Buting advances the defense's framing theory and challenges the burn-site, RAV4, and trailer evidence while emphasizing the State's burden of proof.

Mentioned in this proceeding.

DasseyBrendan DasseyApr 16, 2007 – Apr 25, 2007Called by prosecution

John Ertl testified in Brendan Dassey's 2007 trial about processing the RAV4, sifting burned material, and testing the garage floor. His cross-examination addressed limits in collection methods and whether luminol reactions established the presence of blood.

Day 1

Apr 16, 2007

OpeningState's Opening StatementKenneth R. KratzMentioned

Summary

Kratz outlined the State's theory that Dassey helped Avery assault and kill Halbach, then previewed Dassey's recorded statement and evidence the State said would corroborate it.

Mentioned in this proceeding.

DirectThomas Fassbender — DirectThomas FassbenderKenneth R. KratzMentioned

Summary

Fassbender described the Avery Yard search, RAV4 handling, recovered items, and Dassey's reported February 27 account of garage-floor cleanup; the court limited two exhibit admissions.

Mentioned in this proceeding.

Day 2

Apr 17, 2007

DirectJohn Ertl — DirectJohn ErtlThomas J. Fallon3highlights140lines spoken

Summary

Ertl described the RAV4's recovery, burned debris from a barrel and the burn pit, and the limits of garage luminol testing.

Highlights (3)

testimony highlightErtl described the RAV4's condition at the salvage yard, the decision to defer processing until it reached the laboratory, and its exposure to rain before enclosed transport.Open in transcript →

testimony highlightErtl explained the burn pit sifting process and said that small pieces looked like teeth or bone, but the team was not sure whether they were human remains.Open in transcript →

testimony highlightErtl said multiple garage spots reacted to luminol, but only one tested positive with phenolphthalein; the larger diffuse reaction behind the lawnmower could not be confirmed as blood by that test.Open in transcript →

CrossJohn Ertl — CrossJohn ErtlMark R. Fremgen2highlights82lines spoken

Summary

Fremgen questioned Ertl about limits in the RAV4 search, burn-debris collection, license-plate handling, and garage luminol testing.

Highlights (2)

testimony highlightErtl described looking for a route to the RAV4 but finding no tire tracks or footwear impressions he could discern there; he said he was told impressions on a neighboring vehicle came from officers removing the tarp.Open in transcript →

evidence eventErtl said the fingerprint analyst examined the license plate but, to his knowledge, did not process it at the scene. Ertl packaged it and turned it over to Calumet County; he did not know whether it later reached the Crime Lab.Open in transcript →

Day 3

Apr 18, 2007

DirectThomas Sturdivant — DirectThomas SturdivantThomas J. FallonMentioned

Summary

Sturdivant described suspected bone material at the burn pit, the Crime Lab's sifting and collection, and the admission of related photographs and objects.

Mentioned in this proceeding.

Day 9

Apr 25, 2007

ClosingProsecution closing argument by Thomas J. FallonThomas J. FallonMentioned

Summary

Fallon argued that Dassey's statements were corroborated, that his alleged acts made him a party to all three crimes, and that the jury should return guilty verdicts.

Mentioned in this proceeding.

ClosingDefense closing argument by Mark R. FremgenMark R. FremgenMentioned

Summary

Fremgen argued that forensic gaps and changing details in Dassey's statements left reasonable doubt.

Mentioned in this proceeding.