Preservation of DNA Evidence

and Capital

PostconvictionAppeals

Jackie Nicol and Joan Bundy

Preservation of DNA Evidence for Postconviction Testing

The Issues:

• Collection

• Documentation

• Packaging

• Preservation and storage

• Laws/protocols for keeping evidence after conviction

Brief History of Forensic DNA Typing• 1900 – First useful marker system – ABO blood groups• 1953 – Discovery of the structure of DNA• 1960 – Some 17 or so inherited blood typing systems• 1980 – White describes first polymorphic RFLP marker• 1985 – Jeffreys et al. discovers multilocus VNTR probes and

uses them to exonerate suspect in 2 rape-homicides• 1985 – First scientific paper on PCR• 1986 – First use of PCR-based typing in forensics • 1988 – FBI starts DNA typing• 1991 – First scientific paper on STR typing• 1993 – Kirk Bloodsworth, the first person exonerated from

death row due to postconviction DNA testing• 1998 – FBI launches CODIS database• 2004 – At least 14 persons exonerated by DNA evidence

DNA is remarkably stable It has been identified in:

Egyptian mummies!

Wooly mammoths!

Yet DNA is not always so well preserved.

So what impacts preservation and usability?• How and why biological material is collected

(DNA testing, fingerprinting, serology, etc.)• Moisture level• Light level/type• Impurities (mold, pollen, dirt, bacteria, etc.)• Storage temperature• Storage media (paper/plastic dilemma)• Amount of evidence collected• Sample size available (is one cell enough?)

NIST Study on the Effects of Storage Temperature and Humidity

• Field Samples (318 samples): From state health labs, stored from 2 to 15 yrs Most stored at ambient warehouse

temperatures, one set at -20 ◦C for 6 yrs Dried and sealed??? – conditions not known

(paper/plastic?)

• 4 Control Samples (6 of each sample): NIST prepared, stored for 7.5 yrs Dried in vacuum desiccator, sealed in tubes -198 ◦ C, -80 ◦C, -20 ◦ C and lab ambient

Results of NIST Study

• Typeable DNA was recovered from all samples in all studies

• Some loss of larger loci seen in oldest (15yr) field samples

• Samples stored at ≤ -20 ◦C have intact high molecular weight DNA; ambient samples show signs of degradation

• Mitochondrial DNA was amplified from all storage media types

If humidity is controlled, temperature is not the key to preservation

Technology Advances and Postconviction DNA Testing

• Improved methods have allowed analysis of samples once thought too small

RFLP vs. PCR/STR TOF-Mass Spectrometry is more accurate

that current Capillary Electrophoresis

• Extraction techniques Important for determining the quality of

DNA extracted.

• Human Y-Chromosome Markers

Keys to Optimal Preservation and Forensic Utility

Evidence must be properly: Documented Collected Packaged Preserved and Tested

To meet both the legal and scientific requirements for admissibility in court

Preservation Case Law

• Brady v. Maryland, 373 U.S. 83 (1963) —prosecutor must disclose material that is exculpatory to the accused

• State v. Bryant, 439 F.2d 642 (D.C. Cir. 1971) — duty to disclose cannot be avoided by destroying (or failing to collect) evidence

• State v. Wright, 557 P.2d 1 (Wash. 1976) —failure to preserve murder victim’s clothing violated defendant’s due process rights

Legal Doctrine on Preservation

Factors in assessing whether failure to collect, loss or destruction of evidence worked a deprivation of due process:

(1) Likelihood that lost evidence would have been exculpatory;

(2) Likelihood that defendant was significantly prejudiced at trial by lack of evidence;

(3) Level of government culpability for the loss

Legal Preservation Requirements

• States vary widely: In terms of how long—or even whether—they require preservation of DNA evidence. Key determinant: Where they fall on the finality vs. fairness spectrum.

• Arizona: Requires material kept until all judicial proceedings have ended or, for blood, 35+ years

• CA, MI, NE, NC, OK, TX: Through incarceration

• Florida: Probably the shortest, at two years after final judgment or, for capital cases, 60 days after execution of sentence (or of the person? not clear)

• Colorado: No law enforcement duty to preserve or liability for failure to preserve DNA!

AZ Postconviction DNA TestingRequirements:(1) Defendant convicted of and sentenced for a felony offense(2) Evidence still in the possession of the state or a lab(3) Evidence quantity and quality sufficient for scientific DNA

testing(4) Evidence has not previously been subject to DNA testing or

test desired was not in existence at time of original/prior testing(s) and can resolve an issue not resolvable by the previous test(s)

(5) Reasonable probability that defendant would not have been prosecuted or convicted if exculpatory results had been obtained through DNA testing—court must order testing

(6) Reasonable probability that defendant’s verdict or sentence would have been (merely) more favorable had DNA testing been available at trial, or DNA testing will produce exculpatory evidence (but ∆ likely would still be convicted of some lesser crime)—court may order testing

DNA Testing in Capital Cases

The 10% rule:

• Only about 10% of all death-row appeals have viable DNA component (either no DNA evidence collected or preserved or no ID/actual innocence)

• Only 14 of 115 U.S. exonerations so far due in part to DNA testing (~12%)

The Lucky Ones

Chris Ochoa

Earl Washington Jr.

Kirk Bloodsworth

Ray Krone