Problems in Crime labs Especially the Houston Police Department and Presenting DNA Evidence to a...

Problems in Crime labsProblems in Crime labs

Especially the Houston Especially the Houston Police DepartmentPolice Department

andand

Presenting DNA Evidence to Presenting DNA Evidence to a Jurya Jury

Elizabeth A. Johnson, Ph.D.Elizabeth A. Johnson, Ph.D.

Stupid stuff we’ve seen Stupid stuff we’ve seen while monitoring other labswhile monitoring other labs

Extracting references and unknowns at Extracting references and unknowns at the same time (but on different lab the same time (but on different lab benches, so it’s ok??)benches, so it’s ok??)

Failing to process the extraction blanks in Failing to process the extraction blanks in the same manner as the evidence samplesthe same manner as the evidence samples

Having all the tubes open at onceHaving all the tubes open at once


Touching pipet tips to surfaces, analyst Touching pipet tips to surfaces, analyst raking the pipet tip through his hairraking the pipet tip through his hair

Opening tubes with fingertips, Opening tubes with fingertips, touching inside of tube capstouching inside of tube caps

Inefficient extraction, waste of sampleInefficient extraction, waste of sample


Careless movement between pre- and Careless movement between pre- and post- amplification areaspost- amplification areas

Failing to change gloves, washing off Failing to change gloves, washing off the glovesthe gloves

Losing hairsLosing hairs

Spilling of DNA extract onto the Spilling of DNA extract onto the analyst’s lapanalyst’s lap

CONTAMINATION at TX CONTAMINATION at TX DPSDPS

Mystery female profile appears in 1 of Mystery female profile appears in 1 of 23 cigarette butt samples in October, 23 cigarette butt samples in October, 2000, extraction blank is clean.2000, extraction blank is clean.

Same profile appears in extraction Same profile appears in extraction blank for hair sample in November, blank for hair sample in November, 2001.2001.

Profile is not employees or from other Profile is not employees or from other cases. Profile is still unidentified.cases. Profile is still unidentified.

CONTAMINATION at TX CONTAMINATION at TX DPSDPS

Contamination in a known, profile is Contamination in a known, profile is that of an evidence technician who that of an evidence technician who never handled the sample, extraction never handled the sample, extraction blank is clean.blank is clean.

Contamination by tube to tube carry-Contamination by tube to tube carry-over of DNA, several occurrences.over of DNA, several occurrences.

Contamination by analyst’s own DNA Contamination by analyst’s own DNA in samples, several occurrences.in samples, several occurrences.

Contamination at WSPContamination at WSP

Contamination at Contamination at IdentigeneIdentigene

Identigene is notified by FDLE Tallahasse Identigene is notified by FDLE Tallahasse that data released to them (but not that data released to them (but not associated with their case) shows associated with their case) shows contamination in a reagent blank (EC contamination in a reagent blank (EC fraction)fraction)

Samples from three different cases were Samples from three different cases were processed together in a differential processed together in a differential extraction along with EC and SP reagent extraction along with EC and SP reagent blanksblanks


The DNA in the EC blank is a 1:1 The DNA in the EC blank is a 1:1 mixture and is only male in originmixture and is only male in origin

The SP fraction reagent blank and The SP fraction reagent blank and negative amp control are cleannegative amp control are clean

The DNA in the EC blank has alleles The DNA in the EC blank has alleles in common to sperm samples from in common to sperm samples from two different casestwo different cases


The profile observed in the EC blank The profile observed in the EC blank was explained by “a glove became was explained by “a glove became contaminated during the contaminated during the uncapping/capping of sample tubes uncapping/capping of sample tubes and and allowed DNA from two different allowed DNA from two different samples to be deposited in a third samples to be deposited in a third one (the reagent blank EC)one (the reagent blank EC)””

Stupid stuff we’ve seen (by Stupid stuff we’ve seen (by review, testimony, evidence review, testimony, evidence

re-exam)re-exam)

““Fishing” a profile out of a close mixture Fishing” a profile out of a close mixture and reporting statistics as a single sourceand reporting statistics as a single source

Ignoring other combinations of alleles in Ignoring other combinations of alleles in a mixture to search CODISa mixture to search CODIS

Re-analyzing the data multiple times to Re-analyzing the data multiple times to get noise to label as an allele with get noise to label as an allele with genotypergenotyper

Stupid stuff we’ve seen (by Stupid stuff we’ve seen (by review, testimony, evidence review, testimony, evidence

re-exam)re-exam)

Reporting a result as Reporting a result as inconclusiveinconclusive but but testifying that it testifying that it includesincludes the defendant the defendant

Ignoring all other mechanisms (besides Ignoring all other mechanisms (besides the prosecution’s theory) for DNA to be the prosecution’s theory) for DNA to be on an item of evidenceon an item of evidence

And….And….completely missing biological completely missing biological stainsstains

The Houston The Houston Police Police

DepartmentDepartmentA long history of problemsA long history of problems

The Houston PD DNA labThe Houston PD DNA lab

HPD started their DNA lab in 1991 HPD started their DNA lab in 1991 after sending some serologists to the after sending some serologists to the FBI school for a one month courseFBI school for a one month course

Armed with a flawed cookbook from Armed with a flawed cookbook from the feds, they began to do extractions the feds, they began to do extractions and RFLP testingand RFLP testing

They rarely got results and their own They rarely got results and their own detectives complaineddetectives complained


Circa 1993 they began to Circa 1993 they began to malpractice with a new malpractice with a new technology….PCR technology….PCR

They displayed a total lack of They displayed a total lack of understanding of the concepts of understanding of the concepts of DNA analysis…..DNA analysis…..


The amplification room was in a The amplification room was in a functioning stockroom where pipet tips, functioning stockroom where pipet tips, gloves and other materials used in the gloves and other materials used in the pre-amplification process were storedpre-amplification process were stored

There was only one UV light box in the There was only one UV light box in the lab, so post-product gels were taken lab, so post-product gels were taken into the main extraction lab for into the main extraction lab for photographyphotography


The analysts never ran extraction The analysts never ran extraction blanks (and didn’t understand why blanks (and didn’t understand why they should) until around 1999, then they should) until around 1999, then did so sporadicallydid so sporadically

The analysts who performed DNA The analysts who performed DNA extractions were not trained to do extractions were not trained to do PCR and had no understanding of the PCR and had no understanding of the sensitivity and contamination issuessensitivity and contamination issues


For years they continued to consume For years they continued to consume sample to run a yield gel and make sample to run a yield gel and make failed attempts at RFLP before failed attempts at RFLP before attempting PCRattempting PCR

They failed to use slot blots to They failed to use slot blots to quantify DNA for many years after quantify DNA for many years after slot blots are available, so the PCR slot blots are available, so the PCR amplifications were not optimalamplifications were not optimal


They routinely failed to identify and They routinely failed to identify and isolate sperm which….isolate sperm which….

Resulted in mixtures primarily of Resulted in mixtures primarily of female DNA and…female DNA and…

They routinely and unnecessarily They routinely and unnecessarily consumed evidence making defense consumed evidence making defense retesting impossibleretesting impossible

The Houston PD DNA The Houston PD DNA LabLab

They also……..They also……..

Contaminated samplesContaminated samples

Switched samplesSwitched samples

Incorrectly reported results and Incorrectly reported results and selectively reported resultsselectively reported results

The Houston PD DNA The Houston PD DNA LabLab

Incorrectly reported statistics, grossly Incorrectly reported statistics, grossly favoring the prosecutionfavoring the prosecution

Testified falsely about lab quality Testified falsely about lab quality assurance measuresassurance measures

Testified falsely about results and Testified falsely about results and conclusionsconclusions

Texas v. Patrick Texas v. Patrick PalaciousPalacious

Multiple samples are analyzed and Multiple samples are analyzed and some clearly some clearly exclude the defendantexclude the defendant but are reported as inclusionsbut are reported as inclusions

Texas v. Jaime GarciaTexas v. Jaime Garcia

Texas v. Anthony Texas v. Anthony SmithersSmithers

Anthony Smithers was accused of Anthony Smithers was accused of sexual assault by the daughter of his sexual assault by the daughter of his live-in girlfriend live-in girlfriend

Tissue paper was collected from the Tissue paper was collected from the trash at home…the accuser said she trash at home…the accuser said she wiped herself with this after the wiped herself with this after the assaultassault

Texas v. Anthony Texas v. Anthony SmithersSmithers

The HPD DNA lab analyzes the tissue The HPD DNA lab analyzes the tissue and reports the sperm fraction as a and reports the sperm fraction as a “Match” to Smithers“Match” to Smithers

They never run the nonsperm fraction They never run the nonsperm fraction (the relevant evidence here) to see if it (the relevant evidence here) to see if it is from the girl or her motheris from the girl or her mother

They never analyze a reference from They never analyze a reference from the mother the mother

Problems with the Houston Problems with the Houston PD Crime LabPD Crime Lab

INCOMPETENCE OR FRAUD???INCOMPETENCE OR FRAUD???

Maybe some of both…..Maybe some of both…..


Despite exposures of these practices in Despite exposures of these practices in court in several cases, HPD continues court in several cases, HPD continues until….until….

KHOU-TV airs an investigative report about KHOU-TV airs an investigative report about the HPD DNA lab in November, 2002the HPD DNA lab in November, 2002

The DNA lab fails an external audit and is The DNA lab fails an external audit and is closed in December, 2002 closed in December, 2002


A review of over 400 cases is ordered A review of over 400 cases is ordered and retests are performed (when and retests are performed (when possible) at private labspossible) at private labs

The first case retested (and monitored) The first case retested (and monitored) resulted in an exclusion of Josiah Sutton, resulted in an exclusion of Josiah Sutton, who had served 4 years for sexual who had served 4 years for sexual assault assault

Problems are also detected in the drug Problems are also detected in the drug lab (dry-labbing) and firearms, and the lab (dry-labbing) and firearms, and the toxicology lab is closedtoxicology lab is closed

Even if the analysis Even if the analysis is correct…is correct…

Explaining DNA Explaining DNA to the Juryto the Jury

Putting it all into Putting it all into perspectiveperspective

What does it Mean??What does it Mean??

STR testing is extremely sensitive….STR testing is extremely sensitive….

Approximately 30 diploid cells (200 Approximately 30 diploid cells (200 pg) will be detected at reportable pg) will be detected at reportable levels by most labs (150 RFU)levels by most labs (150 RFU)

How did the evidence get there?? How did the evidence get there?? Transfer?? Duration???Transfer?? Duration???

What does it Mean??What does it Mean??

Seminal fluid contains 20-100 million Seminal fluid contains 20-100 million sperm/mlsperm/ml

A typical ejaculate contains 2-5 ml of A typical ejaculate contains 2-5 ml of semensemen

A drop of seminal fluid will contain at A drop of seminal fluid will contain at least 1 million sperm cellsleast 1 million sperm cells

WA v. Charles JacksonWA v. Charles Jackson Victim and defendant were together all night Victim and defendant were together all night

having sex and doing drugs…cause of death having sex and doing drugs…cause of death undetermined due to decomposition, maybe undetermined due to decomposition, maybe ODOD

Swabs of the victim’s fingernails show a mix Swabs of the victim’s fingernails show a mix of DNA – approx. 80% victim, 20% defendantof DNA – approx. 80% victim, 20% defendant

WSP analyst testifies on direct to the DNA WSP analyst testifies on direct to the DNA mix mix but not that the defendant is a very but not that the defendant is a very minor donorminor donor

WA v. Charles JacksonWA v. Charles Jackson

WSP analyst testifies that the cells from WSP analyst testifies that the cells from the defendant would have to get under the defendant would have to get under the nails by some forceful act such as “a the nails by some forceful act such as “a back scratch or neck rub”, (implying a back scratch or neck rub”, (implying a struggle) and…..struggle) and…..

That the victim likely did not have a That the victim likely did not have a chance to wash her hands after the cells chance to wash her hands after the cells were depositedwere deposited

WA v. Charles JacksonWA v. Charles Jackson

Defense expert points out that, by the Defense expert points out that, by the way…..way…..

The defendant’s DNA is present at a very low The defendant’s DNA is present at a very low level and is no more than 20% of the mixturelevel and is no more than 20% of the mixture

That very few cells of his are present, as few That very few cells of his are present, as few as 30 cells can be detectedas 30 cells can be detected

That if you simply lick your finger to turn a That if you simply lick your finger to turn a page you’ve placed 100s-1000s of cells on page you’ve placed 100s-1000s of cells on your fingeryour finger

That 1000s of his cells could have gotten on That 1000s of his cells could have gotten on her nails during sexher nails during sex

MD v. Tonto CorbinMD v. Tonto Corbin

Victim was a prostitute; crime lab found only Victim was a prostitute; crime lab found only the defendant’s sperm on her vaginal swabsthe defendant’s sperm on her vaginal swabs

Crime lab found semen from three other Crime lab found semen from three other men (not defendant) on her underwear and men (not defendant) on her underwear and clothesclothes

Therefore, State’s theory is the victim never Therefore, State’s theory is the victim never stood up after having sex with the defendant stood up after having sex with the defendant



The number of sperm on the vaginal swab was The number of sperm on the vaginal swab was far too low to be consistent with a full far too low to be consistent with a full ejaculate inside the victim (2 sperm on the ejaculate inside the victim (2 sperm on the entire slide)entire slide)

A small amount of drainage of defendant’s A small amount of drainage of defendant’s semen/sperm could be lost in the large semen/sperm could be lost in the large number of sperm present in the UP from the number of sperm present in the UP from the other manother man



Not all of the stains on the clothing were Not all of the stains on the clothing were testedtested

Drainage is not a constant process….it varies Drainage is not a constant process….it varies widely between women and for the same widely between women and for the same woman with different partnerswoman with different partners

There are no, and cannot be, controlled There are no, and cannot be, controlled studies on drainage because of these variablesstudies on drainage because of these variables

The victim may have changed UPThe victim may have changed UP

AZ v. Martin PriestAZ v. Martin Priest

1 sperm observed on the slide of the 1 sperm observed on the slide of the external genital swabexternal genital swab

AZ DPS policy is not to report anything AZ DPS policy is not to report anything below 150 RFU, so the report says below 150 RFU, so the report says inconclusiveinconclusive

The analyst re-analyzes the data multiple The analyst re-analyzes the data multiple times until 6 artifacts lable with genotyper times until 6 artifacts lable with genotyper = defendant= defendant


The analyst is allowed to give her The analyst is allowed to give her “opinion” of data below 150 RFU“opinion” of data below 150 RFU

She testifies that it excludes all She testifies that it excludes all others tested, so the defendant is others tested, so the defendant is included (the report looks OK, so included (the report looks OK, so ASCLD never knows)ASCLD never knows)


Defense expert points out that, by Defense expert points out that, by the way…..the way…..

The electropherogram is mostly noise The electropherogram is mostly noise at that level, and there are other at that level, and there are other artifacts just as tall that don’t fall on artifacts just as tall that don’t fall on ladderladder

The analyst has violated her lab’s The analyst has violated her lab’s policy with her testimonypolicy with her testimony

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