Shawn Montpetit, DNA Technical Manager San Diego Police Department Crime Laboratory

Transcription

1 Shawn Montpetit, DNA Technical Manager San Diego Police Department Crime Laboratory 2014 Qiagen North American User s Group Meeting Houston, TX 2014

2 QIAGEN would like to thank our speaker, Shawn Montpetit, for his presentation. Disclaimer: QIAGEN is not affiliated with the San Diego Police Department Crime Laboratory. The views expressed herein are those of the speaker, and do not necessarily express the views of QIAGEN. For up-to-date licensing information and product-specific disclaimers for QIAGEN products, see the respective QIAGEN kit handbook or user manual. QIAGEN kit handbooks and user manuals are available at or can be requested from QIAGEN Technical Services or your local distributor.

3 Services population of about 1.3 million } ~1700 lab work requests received in 2013 } ~1/4 were crimes of a violent or sexual nature } Forensic Biology Unit has 17 Criminalists 2 full-time Y-screen analysts 2 full-time DNA analysts for sexual assault } Lab located at SDPD headquarters Frequent communication with Sex Crimes & Child Abuse Units

4 2008 AAFS 2008 JFS th ISHI

5 DNA/Biology Requests by year

6 } SDPD Brought the Y-screen protocol online in Increased sample volume to quant. July SWGDAM Meeting } CSFS in Toronto, Canada currently using a Y-screen approach } Michigan State Police currently using a Y-screen approach } Cal-DOJ has a RADs program for SAEKs. } FBI is examining elimination of serology.

7 } Initially just SAEK from adult females Including body swabs (breast, neck, etc) These had not been screened via microscopy } Expanded to include juveniles (CHAB cases) Microscopy on negative kits } Began to incorporate clothing Several groper series swabbed area groped Cuttings and/or swabbings of clothing These are being tested in a more timely fashion

8 } 1 case at a time } Sperm cases only } Labor intensive, no automation } Approximations of DNA present based on # cells observed } Evidence consumed } Must re-sample for DNA analysis } 5-7+ cases at a time } All male DNA cases } Labor automated via existing robotics } Approximations of DNA present based on Quant Duo results } Evidence not consumed } Remaining DNA extracts can be amplified directly Traditional Y-screen

9 Microscopy Quantifiler Duo Sample Size ¼ swab ¼ swab Automated no YES Time varies per sample (high) varies per sample (low) Sample consumed yes NO Confirms semen YES no Estimates male DNA not directly YES

10 } # full-time screeners: 4 in in 2013 } Per analyst per month: 7-8 cases (microscopy) cases (Y-screen) } 96% increase in screening efficiency } 341 vs. 435 total cases screened Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Microscopy Y-screen

11 } All male on female sexual assault evidence analyzed via Y-screen } Presumptive testing } DNA extraction and quantitation (20% of sample) } Samples with sufficient male DNA are DNA tested Determined via consultation with DNA analyst Confirmation of semen during differential extraction Amylase tested for more often during differential Y-screen extracts sometimes amplified directly } Microscopy of additional sample portion in child abuse cases with insufficient male DNA

12 Day Y-screen results obtained DNA request submitted Verbal results to investigator within 1 week! DNA typing results obtained

13 } Typical timeline for sexual assault casework: Day Y-screen results obtained DNA request submitted DNA typing results obtained } Oral copulation case (unknown S) from 2013: Day Potential S identified via tip, reference collected Y-screen results obtained, Investigator requested rush DNA analysis Y-screen DNA extracts from vaginal, external genital, and left thigh swabs directly amplified & typed (rush): 1) S matched to left thigh swabs via ID+ 2) S matched to vaginal & external genital swabs via Yfiler 1 day turnaround time!

14 } Typical timeline for sexual assault casework: Day Y-screen results obtained DNA request submitted DNA typing results obtained } Recent groping case (unknown S): Day references Day 1: Male DNA detected on swab of mouth area Day 7: One suspect matched to swab of mouth area Day 2: Predominant Y-STR profile developed from Y-screen DNA extract 1 week from start to finish!

15 } Kit collected & sampled for Y-screen: Kit Item AP P30 Male DNA Vulvar swabs + - Yes Sperm Insufficient # for DNA testing CODIS-eligible profile? Yes; sperm fraction Neck swabs - - Yes None Yes } Male profile from DIFFERENT unknown male developed from vulvar swabs!

16 } Three cases of females drinking with friends/ acquaintances and waking up to suspect raping them } No sperm detected on any case } Male profiles developed in all three cases: CODIS-eligible Y-STR profile Y-STR profile } If DNA testing was based on microscopy for presence of sperm cells, all three overlooked

17 } Both SART kits negative for sperm cells } All clothing examined, 1 of 2 suspects not detected on any evidence } Kits re-evaluated via Y-screen Vulvar swab of one victim positive for male DNA No sperm observed during differential extraction } Y-STR profile from vulvar swabs matched 2 nd suspect

18 } Education and training of investigators and attorneys } More samples sperm negative with male DNA } Interpretation of Y-screen results on clothing Is the male DNA present relevant to the assault? } A number of samples have very low male DNA Could they be stochastic issues?

19 } Looking to capitalize on the incorporation of the QIAsymphony. n Flexible sample input: microtubes or plates n Flexible eluate transfer into microtubes or plates n Flexible elution volumes for each protocol n Plate bar code reading and placement verification Batch processing SA samples from multiple Y-screen analysts into plates.

20 n Cooled position for storage of sensitive eluates and overnight runs n Non-cooled MTP-format slots (3) n Flexible eluate transfer into microtubes or plates* n Flexible elution volumes for each protocol n Plate bar code reading and placement verification Contamination prevention n Optimized design and protocols n Moving UV light and drop catchers n Hooded system with magnetic locks n Separate and safe waste disposal

21 } Y-screen has increased the number of probative cases submitted for DNA analysis vs. traditional microscopy May be missing some probative low sperm cases Also catching previously overlooked cases involving oral copulation, digital penetration, groping, etc. } Y-screen can be automated Higher throughput and quicker turnaround time } Y-screen has helped weed out non-probative cases using less resources

22 } Investigators & attorneys happier with faster results } Automation is flexible with the workstations currently employed } If we get a mandate to test all kits, we can get that work done in a more efficient manner with less disruption to other cases

23 Shawn Montpetit Tel: