Lessons Learned from Multi-Perpetrator DNA Cases Edwin Grimsley, Case Analyst - The Innocence Project - PowerPoint PPT Presentation

1 / 25
About This Presentation
Title:

Lessons Learned from Multi-Perpetrator DNA Cases Edwin Grimsley, Case Analyst - The Innocence Project

Description:

* * * * * * * * * * * * * * * * * * * * * In cases where the number of perpetrators is definitively known, DNA testing can conclusively prove a defendant s ... – PowerPoint PPT presentation

Number of Views:222
Avg rating:3.0/5.0
Slides: 26
Provided by: IP79
Learn more at: https://law.umkc.edu
Category:

less

Transcript and Presenter's Notes

Title: Lessons Learned from Multi-Perpetrator DNA Cases Edwin Grimsley, Case Analyst - The Innocence Project


1
Lessons Learned from Multi-Perpetrator DNA
CasesEdwin Grimsley, Case Analyst - The
Innocence Project
2
Why Multi-Perpetrator DNA Cases?
  • In cases where the number of perpetrators is
    definitively known, DNA testing can conclusively
    prove a defendants innocence.
  • We can definitively know the number of
    perpetrators when victim(s) or witness(es)
    provide a clear account with a fixed number of
    perpetrators.
  • Because we know number of perpetrators, proving
    innocence through DNA differs from un-witnessed
    cases.

3
  • Of the nearly 300 DNA exonerations, there are 22
    cases where a victim or witness at the crime
    scene said there were multiple perpetrators
    involved.
  • These multi-perpetrator DNA cases represent 29
    exonerations.

4
Lessons Weve Learned from Multi-Perpetrator DNA
Cases
  • Lesson 1 You can prove one of the alleged
    perpetrators innocent even when his
    co-defendant/alleged co-perpetrator is included
    by DNA testing or claims guilt.
  • Lesson 2 You cannot assume that someone is not
    innocent just because they havent requested help
    from an Innocence Project.
  • Lesson 3 Multi-Perpetrator DNA cases can be
    broken down into a few core principles.

5
Lawrence McKinney
  • Lawrence McKinney spent 31.5 years in the
    Tennessee prison system for a rape he did not
    commit. In 2009, DNA testing excluded McKinney as
    one of the individuals involved in a two
    perpetrator rape of a single victim.
  • Michael Yancey, who was McKinneys co-defendant,
    wrote to the Innocence Project claiming
    innocence. The Innocence Project accepted Michael
    Yanceys case in 2007.

6
  • Lesson 1 You can prove one of the alleged
    perpetrators innocent even when his
    co-defendant/alleged co-perpetrator is included
    by DNA testing or claims guilt.

7
Background Info Victim
  • 30 years old
  • One victim, female
  • Lived with boyfriend and two children in Memphis,
    TN
  • Boyfriend at work on the night of the crime
  • Victim was asleep in her bed

8
Two perpetrators (P1 and P2) enter Vs home
around 5 am.
9
P1 and P2 demand money. V refuses. P1 sexually
assaults V in her bed. V reports that P1
ejaculates.
10
P2 subsequently rapes V. V reports that P2
ejaculates.
11
Both P1 and P2 ejaculate Wed look for two DNA
profiles.
12
Victim tells Police I saw two assailants and
both raped me.
V was brought to a hospital where a rape kit was
collected.
13
Identification/Arrest
  • Victim believed both assailants lived in her
    building she identified them as Michael (P1)
    and his friend (P2) whom she did not know well.
  • Michael Yancey (P1) and Lawrence McKinney (P2),
    who lived in the building, were arrested within
    an hour of the crime.

14
Innocence Claims
  • Michael Yancey told us that he was not at the
    crime scene. Yancey named another man (not
    Lawrence McKinney) as the actual perpetrator.
  • We did not know Lawrence McKinneys claims at the
    time of acceptance. McKinney claimed innocence
    when DNA sample was collected.
  • We sought to test DNA profiles of Yancey,
    McKinney, and the alternate perpetrator.

15
Three scenarios to prove innocence
  • Two foreign DNA profiles that excluded V would be
    obtained. The profiles would not match Michael
    Yancey, Lawrence McKinney, or the victims
    boyfriend.
  • Two foreign DNA profiles that excluded V would be
    obtained. One profile would match Lawrence
    McKinney and a second profile would exclude
    Michael Yancey and the victims boyfriend.
  • One foreign DNA profile that excluded V would be
    obtained. The profiles would not match Michael
    Yancey or Lawrence McKinney. The foreign profile
    would be uploaded into a DNA database and hit to
    somebody with no connection to Yancey or
    McKinney.

16
DNA test Results
  • The rape kit was not located. Semen was
    identified on bedsheets and Vs panties. DNA
    mixture of at least two individuals was found on
    both the panties and bedsheets and these DNA
    profiles were consistent with each other.
  • Michael Yancey could not be excluded from one of
    the profiles and could not be proven innocent.
  • Lawrence McKinney was excluded from both
    profiles, proving his innocence.

17
Arthur Mumphrey Exoneration
  • Co-defendant Steve Thomas admitted his
    involvement to the police. Thomas named Mumphrey
    as his co-perpetrator.
  • Two perpetrator rape. Both perpetrators raped a
    single victim.

18
  • Mumphrey, who claimed innocence, hired a local
    Houston attorney to pursue DNA testing. Vs rape
    kit and underwear were DNA tested. Two profiles
    were developed that matched Steve Thomas and an
    unknown male.
  • Mumphrey was excluded and subsequently
    exonerated.

19
  • Lesson 2 You cannot assume that someone is not
    innocent just because they havent requested help
    from an Innocence Project.
  • Lawrence McKinney did not contact the Innocence
    Project or other organizations.

20
Reasons why innocent defendants/co-defendants do
not contact attorneys/organizations
  1. Limited knowledge of attorneys or organizations
    to contact because of poor jail resources
  2. Mental Health Issues
  3. Gave Up Fight after Incarcerated

21
  • Literacy
  • Does Not Understand Science or Legal Process

22
  • Lesson 3 Multi-Perpetrator DNA cases can be
    broken down into a few core principles.

23
  • We must account for every perpetrator alleged to
    have participated in the crime.
  • Two things to look for in Multi-Perpetrator cases
    with a live victim/witness
  • Victim or witness defines number of perpetrators.
  • Match each perpetrator seen to a specific profile
    on crime scene evidence.

24
(No Transcript)
25
Scenario Trump Card?
  • Alternative to the traditional Multi-Perpetrator
    theory
  • CODIS/Database hit to someone unrelated.
  • Match to alternate perpetrator who committed
    crime with another person.
Write a Comment
User Comments (0)
About PowerShow.com