jeff thompson assistant laboratory director serology/dna unit scientific investigation division los...
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Logistical Considerations to “Test Every Rape Kit”
Jeff ThompsonAssistant Laboratory Director
Serology/DNA UnitScientific Investigation DivisionLos Angeles Police Department
ASCLD 42nd Annual SymposiumApril 29, 2015
2008-2009 Backlog of (unrequested) kits: 6,132 Average # of kits received per month:
~105 Number of bench DNA analysts: ~10
◦ Few kits requested & tested◦ Extensive use of outsourcing◦ Turnaround time: >>120 days
Changes & Expectations◦ New hires since 2008: 40+◦ Goals
Turnaround time <90 days Test ALL kits without outsourcing
LAPD, we have a problem…
DNA testing determined by◦Sperm rating
Microscopy is time-consuming (especially if the kit is negative & includes slides generated by SART nurse)
◦Presence of nucleated epithelial cells on dried secretions E. Cells probative or not?
Perioral swab? Thigh swab? Minor’s left hand?
Concerns with existing screening protocol - Microscopy & Probative
Medical Report◦ Information not always consistent with
request submitted by Detectives Which one do you trust?
◦ Do you screen only the probative items based on the allegations? What if victim reports Loss of
Consciousness/Loss of Memory (LOC/LOM)?◦ What do you do if the alleged act is digital
penetration? Groping?
More concerns
Inspiration from Georgia Bureau of Investigation◦Switched from microscopy to Quantifiler Duo for screening rape kits
◦Achieved significant gains in screening productivity
Solution
Sexual Assault Evidence Kit
(SAEK)
Document SAEK Contents & Sample
Swabs
Water ExtractionMicroscopy
3µL aliquot to slide “pre-extraction”
Return to SAEK to sample swabs
Differential/Non-Differential extraction
(lyse e. cells)
Microscopy3µL aliquot to slide “post-extraction”
Sperm digest EZ1 CleanupQuant DuoMale DNA
GBI Procedural Modification
GB
I
GBI
Sexual Assault Evidence Kit
(SAEK)
Document SAEK Contents & Sample
Swabs
Water ExtractionMicroscopy
3µL aliquot to slide “pre-extraction”
Return to SAEK to sample swabs
Differential/Non-Differential extraction
(lyse e. cells)
Microscopy3µL aliquot to slide “post-extraction”
Sperm digestEZ1/QiaSymphony
CleanupQuant DuoMale DNA
LAPD MSD Procedural Modification
LAPD MSD
Male Screen Detail Program (MSD) Goals◦ Increase efficiency of screening
Quantifiler Duo Touch SAEK one time only
◦ Lower turn around times Write one report
◦ Expand duties of new hires DNA Technicians (Screeners trained to
extract/quant) Extracts passed on to DNA analysts Can employ personnel without DNA
coursework
Revamped Screening of Sexual Assault Evidence Kit (SAEK)
DNA Analyst “Triage” – Determining samples to
amplify Scientific Data
◦ Sperm Results◦ Male quantitation (Quantifiler Duo)◦ Male: Female Ratio (Quantifiler Duo)
Case Scenario◦ Single Suspect vs. Multiple Suspect◦ Consenting Partner◦ Minor Victim◦ Loss of Consciousness / Loss of Memory◦ Male Victim or Female Suspect
Combining Sperm and Quant Duo Results For Differential Samples
Category 2Sperm Rating >1Quant Duo =1-15 pg/µL
* 3% of samples
Category 1Sperm Rating >1Quant Duo >15 pg/µL
* 15% of samples
Category 3Sperm Rating >1Quant Duo =undetected
* 1% of samples
Category 4Sperm Rating= 0Quant Duo > 15 pg/µL
* 8% of samples
Category 5Sperm Rating = 0Quant Duo =1-15 pg/µL
* 14% of samples
Category 6Sperm Rating = 0Quant Duo = undetected
* 59% of samples
Official start date: December 3, 2012 1 Supervising Criminalist for case
management and admin reviews 9 DNA technicians 11 DNA analysts Rotational duties – 2 DNA techs
assigned to non-diff extractions and quants per week
DNA analysts float into tech positions, as needed
Male Screen Detail (MSD)
Turnaround time defined as:◦DATE REQUEST RECEIVED to DATE REPORT ADMIN REVIEWED Average 63 days Range 2-90 days
Current Stats
SAEK Turn Around Time
1/1/20127/1/20121/1/20137/1/20131/1/20140
50
100
150
200
250 Number of Kits In Progress Over Indicated Time
over 180 daysover 150 daysover 120 daysover 90 days
MS D
LAPD MSD process vs. LAPD “Old Way”◦Processing all kits with fewer personnel than “old way” would require Increased reagent costs offset by salary savings from increased productivity
◦Faster turn-around ◦Superior analytical results
Comparisons
How does MSD compare to other methods?◦Selective sampling (Fast Track Forensics –
FTF) used in Los Angeles for several years SART Nurse collects additional swabs &
submits directly to state lab for DNA extraction and typing (no screening) Based on victim statements and physical
findings FTF continued after implementation of
LAPD MSD Cases have been processed by both methods
Comparisons
Randomly selected 50 cases processed both by selective sampling (FTF) & MSD◦ Compared number of:
swabs examined profiles developed CODIS uploads
Cases included◦ 42% of victims reported loss of
consciousness or loss of memory
Comparisons
Average # of swabs screened per SAEK ◦MSD = 7.6◦FTF = 0 (unscreened, all are DNA typed)
Average # of swabs DNA typed per SAEK◦MSD = 2.6◦FTF = 2.6
Comparisons
MSD FTF0
5
10
15
20
25
30
25
11
Unique CODIS Uploads (Out of 50 Cases)
CODIS Uploads
MSD vs. FTF – CODIS Uploads
Will a detective recognize not all SAEK profiles were detected and request additional work?◦LAPD had assumed detectives would request all SAEKs be tested that should be tested. Of the 6,132 unexamined SAEKs identified
in the freezer audit:
Over 400 were stranger rapes
Further Considerations
Link cases◦ Rapes in two different cities (without an
arrest) won’t be linked otherwise◦ DDA’s will not file many cases with
vulnerable victims or consent issues Some criminals know this and deliberately
target vulnerable victims or develop “plausible” consent
Without filing, no arrest and no entry into CODIS◦ Multiple CODIS hits to the same offender can
encourage a DDA to file cases Multiple victims (even with credibility issues)
can corroborate each other
Why Do We Test Every SAEK?
Gary Ridgway◦“Green River Killer”◦Convicted of killing 49 (likely over 70)◦Targeted prostitutes & runaways◦Ridgway “took advantage of (prostitute)
services regularly”
Further Considerations
William Suff◦“Lake Elsinore Killer”/“Riverside
Prostitute Killer”◦Convicted of killing 12 (likely 22)◦Targeted prostitutes◦Suff escalated throughout his spree
Further Considerations
Did they start with murder, or sexual assault?◦ Was their first violent crime a homicide, or a
sexual assault? If the latter, did missed opportunities to link cases
allow them to victimize others & further hone their “skills” to avoid detection & prosecution?
◦ Could their killing sprees have been cut short or eliminated altogether if CODIS had linked them to the reported sexual assaults of multiple vulnerable victims?
Final Considerations
Lab Director Doreen Hudson◦ Had us examine other methods to back up our
consensus that we were doing things better
Supervising Criminalist Mike Mastrocovo ◦ Took GBI’s method and expanded it dramatically
Serology/DNA Unit◦ Did a ton of case work, validations & innovations,
under intense media scrutiny & Department pressure, to get us to where we are today
Acknowledgements
