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Problems in Crime labs Especially the Houston Police Department and Presenting DNA Evidence to a Jury Elizabeth A. Johnson, Ph.D.

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Presentation on theme: "Problems in Crime labs Especially the Houston Police Department and Presenting DNA Evidence to a Jury Elizabeth A. Johnson, Ph.D."— Presentation transcript:

1 Problems in Crime labs Especially the Houston Police Department and Presenting DNA Evidence to a Jury Elizabeth A. Johnson, Ph.D.

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3 Stupid stuff weve seen while monitoring other labs Extracting references and unknowns at the same time (but on different lab benches, so its ok??) Extracting references and unknowns at the same time (but on different lab benches, so its ok??) Failing to process the extraction blanks in the same manner as the evidence samples Failing to process the extraction blanks in the same manner as the evidence samples Having all the tubes open at once Having all the tubes open at once

4 Stupid stuff weve seen while monitoring other labs Touching pipet tips to surfaces, analyst raking the pipet tip through his hair Touching pipet tips to surfaces, analyst raking the pipet tip through his hair Opening tubes with fingertips, touching inside of tube caps Opening tubes with fingertips, touching inside of tube caps Inefficient extraction, waste of sample Inefficient extraction, waste of sample

5 Stupid stuff weve seen while monitoring other labs Careless movement between pre- and post- amplification areas Careless movement between pre- and post- amplification areas Failing to change gloves, washing off the gloves Failing to change gloves, washing off the gloves Losing hairs Losing hairs Spilling of DNA extract onto the analysts lap Spilling of DNA extract onto the analysts lap

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10 CONTAMINATION at TX DPS Mystery female profile appears in 1 of 23 cigarette butt samples in October, 2000, extraction blank is clean. Mystery female profile appears in 1 of 23 cigarette butt samples in October, 2000, extraction blank is clean. Same profile appears in extraction blank for hair sample in November, Same profile appears in extraction blank for hair sample in November, Profile is not employees or from other cases. Profile is still unidentified. Profile is not employees or from other cases. Profile is still unidentified.

11 CONTAMINATION at TX DPS Contamination in a known, profile is that of an evidence technician who never handled the sample, extraction blank is clean. Contamination in a known, profile is that of an evidence technician who never handled the sample, extraction blank is clean. Contamination by tube to tube carry-over of DNA, several occurrences. Contamination by tube to tube carry-over of DNA, several occurrences. Contamination by analysts own DNA in samples, several occurrences. Contamination by analysts own DNA in samples, several occurrences.

12 Contamination at WSP

13 Contamination at Identigene Identigene is notified by FDLE Tallahasse that data released to them (but not associated with their case) shows contamination in a reagent blank (EC fraction) Identigene is notified by FDLE Tallahasse that data released to them (but not associated with their case) shows contamination in a reagent blank (EC fraction) Samples from three different cases were processed together in a differential extraction along with EC and SP reagent blanks Samples from three different cases were processed together in a differential extraction along with EC and SP reagent blanks

14 Contamination at Identigene The DNA in the EC blank is a 1:1 mixture and is only male in origin The DNA in the EC blank is a 1:1 mixture and is only male in origin The SP fraction reagent blank and negative amp control are clean The SP fraction reagent blank and negative amp control are clean The DNA in the EC blank has alleles in common to sperm samples from two different cases The DNA in the EC blank has alleles in common to sperm samples from two different cases

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

16 Stupid stuff weve seen (by review, testimony, evidence re-exam) Fishing a profile out of a close mixture and reporting statistics as a single source Fishing a profile out of a close mixture and reporting statistics as a single source Ignoring other combinations of alleles in a mixture to search CODIS Ignoring other combinations of alleles in a mixture to search CODIS Re-analyzing the data multiple times to get noise to label as an allele with genotyper Re-analyzing the data multiple times to get noise to label as an allele with genotyper

17 Stupid stuff weve seen (by review, testimony, evidence re-exam) Reporting a result as inconclusive but testifying that it includes the defendant Reporting a result as inconclusive but testifying that it includes the defendant Ignoring all other mechanisms (besides the prosecutions theory) for DNA to be on an item of evidence Ignoring all other mechanisms (besides the prosecutions theory) for DNA to be on an item of evidence And….completely missing biological stains And….completely missing biological stains

18 The Houston Police Department A long history of problems

19 The Houston PD DNA lab HPD started their DNA lab in 1991 after sending some serologists to the FBI school for a one month course HPD started their DNA lab in 1991 after sending some serologists to the FBI school for a one month course Armed with a flawed cookbook from the feds, they began to do extractions and RFLP testing Armed with a flawed cookbook from the feds, they began to do extractions and RFLP testing They rarely got results and their own detectives complained They rarely got results and their own detectives complained

20 The Houston PD DNA lab Circa 1993 they began to malpractice with a new technology….PCR Circa 1993 they began to malpractice with a new technology….PCR They displayed a total lack of understanding of the concepts of DNA analysis….. They displayed a total lack of understanding of the concepts of DNA analysis…..

21 The Houston PD DNA lab The amplification room was in a functioning stockroom where pipet tips, gloves and other materials used in the pre-amplification process were stored The amplification room was in a functioning stockroom where pipet tips, gloves and other materials used in the pre-amplification process were stored There was only one UV light box in the lab, so post-product gels were taken into the main extraction lab for photography There was only one UV light box in the lab, so post-product gels were taken into the main extraction lab for photography

22 The Houston PD DNA lab The analysts never ran extraction blanks (and didnt understand why they should) until around 1999, then did so sporadically The analysts never ran extraction blanks (and didnt understand why they should) until around 1999, then did so sporadically The analysts who performed DNA extractions were not trained to do PCR and had no understanding of the sensitivity and contamination issues The analysts who performed DNA extractions were not trained to do PCR and had no understanding of the sensitivity and contamination issues

23 The Houston PD DNA lab For years they continued to consume sample to run a yield gel and make failed attempts at RFLP before attempting PCR For years they continued to consume sample to run a yield gel and make failed attempts at RFLP before attempting PCR They failed to use slot blots to quantify DNA for many years after slot blots are available, so the PCR amplifications were not optimal They failed to use slot blots to quantify DNA for many years after slot blots are available, so the PCR amplifications were not optimal

24 The Houston PD DNA lab They routinely failed to identify and isolate sperm which…. They routinely failed to identify and isolate sperm which…. Resulted in mixtures primarily of female DNA and… Resulted in mixtures primarily of female DNA and… They routinely and unnecessarily consumed evidence making defense retesting impossible They routinely and unnecessarily consumed evidence making defense retesting impossible

25 The Houston PD DNA Lab They also…….. Contaminated samples Contaminated samples Switched samples Switched samples Incorrectly reported results and selectively reported results Incorrectly reported results and selectively reported results

26 The Houston PD DNA Lab Incorrectly reported statistics, grossly favoring the prosecution Incorrectly reported statistics, grossly favoring the prosecution Testified falsely about lab quality assurance measures Testified falsely about lab quality assurance measures Testified falsely about results and conclusions Testified falsely about results and conclusions

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28 Texas v. Patrick Palacious Multiple samples are analyzed and some clearly exclude the defendant but are reported as inclusions Multiple samples are analyzed and some clearly exclude the defendant but are reported as inclusions

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30 Texas v. Jaime Garcia

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33 Texas v. Anthony Smithers Anthony Smithers was accused of sexual assault by the daughter of his live-in girlfriend Anthony Smithers was accused of sexual assault by the daughter of his live-in girlfriend Tissue paper was collected from the trash at home…the accuser said she wiped herself with this after the assault Tissue paper was collected from the trash at home…the accuser said she wiped herself with this after the assault

34 Texas v. Anthony Smithers The HPD DNA lab analyzes the tissue and reports the sperm fraction as a Match to Smithers The HPD DNA lab analyzes the tissue and reports the sperm fraction as a Match to Smithers They never run the nonsperm fraction (the relevant evidence here) to see if it is from the girl or her mother They never run the nonsperm fraction (the relevant evidence here) to see if it is from the girl or her mother They never analyze a reference from the mother They never analyze a reference from the mother

35 Problems with the Houston PD Crime Lab INCOMPETENCE OR FRAUD??? Maybe some of both…..

36 Problems with the Houston PD Crime Lab Despite exposures of these practices in court in several cases, HPD continues until…. Despite exposures of these practices in court in several cases, HPD continues until…. KHOU-TV airs an investigative report about the HPD DNA lab in November, 2002 KHOU-TV airs an investigative report about the HPD DNA lab in November, 2002 The DNA lab fails an external audit and is closed in December, 2002 The DNA lab fails an external audit and is closed in December, 2002

37 Problems with the Houston PD Crime Lab A review of over 400 cases is ordered and retests are performed (when possible) at private labs A review of over 400 cases is ordered and retests are performed (when possible) at private labs The first case retested (and monitored) resulted in an exclusion of Josiah Sutton, who had served 4 years for sexual assault The first case retested (and monitored) resulted in an exclusion of Josiah Sutton, who had served 4 years for sexual assault Problems are also detected in the drug lab (dry- labbing) and firearms, and the toxicology lab is closed Problems are also detected in the drug lab (dry- labbing) and firearms, and the toxicology lab is closed

38 Even if the analysis is correct…

39 Explaining DNA to the Jury Putting it all into perspective

40 What does it Mean?? STR testing is extremely sensitive…. Approximately 30 diploid cells (200 pg) will be detected at reportable levels by most labs (150 RFU) Approximately 30 diploid cells (200 pg) will be detected at reportable levels by most labs (150 RFU) How did the evidence get there?? Transfer?? Duration??? How did the evidence get there?? Transfer?? Duration???

41 What does it Mean?? Seminal fluid contains million sperm/ml Seminal fluid contains million sperm/ml A typical ejaculate contains 2-5 ml of semen A typical ejaculate contains 2-5 ml of semen A drop of seminal fluid will contain at least 1 million sperm cells A drop of seminal fluid will contain at least 1 million sperm cells

42 WA v. Charles Jackson Victim and defendant were together all night having sex and doing drugs…cause of death undetermined due to decomposition, maybe OD Victim and defendant were together all night having sex and doing drugs…cause of death undetermined due to decomposition, maybe OD Swabs of the victims fingernails show a mix of DNA – approx. 80% victim, 20% defendant Swabs of the victims fingernails show a mix of DNA – approx. 80% victim, 20% defendant WSP analyst testifies on direct to the DNA mix but not that the defendant is a very minor donor WSP analyst testifies on direct to the DNA mix but not that the defendant is a very minor donor

43 WA v. Charles Jackson WSP analyst testifies that the cells from the defendant would have to get under the nails by some forceful act such as a back scratch or neck rub, (implying a struggle) and….. WSP analyst testifies that the cells from the defendant would have to get under the nails by some forceful act such as a back scratch or neck rub, (implying a struggle) and….. That the victim likely did not have a chance to wash her hands after the cells were deposited That the victim likely did not have a chance to wash her hands after the cells were deposited

44 WA v. Charles Jackson Defense expert points out that, by the way….. The defendants DNA is present at a very low level and is no more than 20% of the mixture The defendants DNA is present at a very low level and is no more than 20% of the mixture That very few cells of his are present, as few as 30 cells can be detected That very few cells of his are present, as few as 30 cells can be detected That if you simply lick your finger to turn a page youve placed 100s-1000s of cells on your finger That if you simply lick your finger to turn a page youve placed 100s-1000s of cells on your finger That 1000s of his cells could have gotten on her nails during sex That 1000s of his cells could have gotten on her nails during sex

45 MD v. Tonto Corbin Victim was a prostitute; crime lab found only the defendants sperm on her vaginal swabs Victim was a prostitute; crime lab found only the defendants sperm on her vaginal swabs Crime lab found semen from three other men (not defendant) on her underwear and clothes Crime lab found semen from three other men (not defendant) on her underwear and clothes Therefore, States theory is the victim never stood up after having sex with the defendant Therefore, States theory is the victim never stood up after having sex with the defendant

46 MD v. Tonto Corbin Defense expert points out that, by the way….. The number of sperm on the vaginal swab was far too low to be consistent with a full ejaculate inside the victim (2 sperm on the entire slide) The number of sperm on the vaginal swab was far too low to be consistent with a full ejaculate inside the victim (2 sperm on the entire slide) A small amount of drainage of defendants semen/sperm could be lost in the large number of sperm present in the UP from the other man A small amount of drainage of defendants semen/sperm could be lost in the large number of sperm present in the UP from the other man

47 MD v. Tonto Corbin Defense expert points out that, by the way….. Not all of the stains on the clothing were tested Not all of the stains on the clothing were tested Drainage is not a constant process….it varies widely between women and for the same woman with different partners Drainage is not a constant process….it varies widely between women and for the same woman with different partners There are no, and cannot be, controlled studies on drainage because of these variables There are no, and cannot be, controlled studies on drainage because of these variables The victim may have changed UP The victim may have changed UP

48 AZ v. Martin Priest 1 sperm observed on the slide of the external genital swab 1 sperm observed on the slide of the external genital swab AZ DPS policy is not to report anything below 150 RFU, so the report says inconclusive AZ DPS policy is not to report anything below 150 RFU, so the report says inconclusive The analyst re-analyzes the data multiple times until 6 artifacts lable with genotyper = defendant The analyst re-analyzes the data multiple times until 6 artifacts lable with genotyper = defendant

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50 AZ v. Martin Priest The analyst is allowed to give her opinion of data below 150 RFU The analyst is allowed to give her opinion of data below 150 RFU She testifies that it excludes all others tested, so the defendant is included (the report looks OK, so ASCLD never knows) She testifies that it excludes all others tested, so the defendant is included (the report looks OK, so ASCLD never knows)

51 AZ v. Martin Priest Defense expert points out that, by the way….. The electropherogram is mostly noise at that level, and there are other artifacts just as tall that dont fall on ladder The electropherogram is mostly noise at that level, and there are other artifacts just as tall that dont fall on ladder The analyst has violated her labs policy with her testimony The analyst has violated her labs policy with her testimony

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