Carol Rogers Lead Scientist Sexual Offences NOT PROTECTIVELY

Carol Rogers Lead Scientist – Sexual Offences NOT PROTECTIVELY MARKED

Forensic investigations into sexual offences • Sex offence cases usually rely heavily on Forensic science, due to lack of witnesses • Every contact leaves a trace – semen to ‘touch’ DNA • Types of Forensic evidence that can assist and the limitations • Case studies • Recent developments NOT PROTECTIVELY MARKED

Sexual Offences • Used to be about 20% of case work, now approaching half • Forensic requests to; - establish intercourse/penetration - establish contact - examine for textile damage NOT PROTECTIVELY MARKED

PROFILE OF SEXUAL OFFENCES CASES • 842 SOSA cases submitted to SPA last year, 50% in West • Stranger, section 1 sexual assaults – less than 5% • Semen found in about 33% cases • The shortest interval between disclosure to police and medical examination of female complainants is 4 hours • Personal observation of increase in cases involving those under 16

Before We Start…. • Medical forms To devise an exam strategy we need to know; Date/time of incident Date/time of medical Extent of washing/ bathing As much detail as possible about the incident (limited with child victims) Also useful to know (for adult victims)– last, previous intercourse, menstruating Samples taken should follow FFLM guidelines (guidelines apply to child victims too) NOT PROTECTIVELY MARKED

Sex Offences investigations • • Depending on case circumstance but usually, Initial examination is for seminal fluid Intimate swabs Clothing Items seized from locus – e. g bedding Crime scene attendance Quick chemical test – Acid Phosphatase Microscopically confirmed

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Scene Examination Potential to examine immovable items or surfaces such as: • Cars • Fixed sofa cushions • Floors • Outdoor areas (weather dependant) • AP as in lab assisted by UV light

Sexual Offences - TSI • In case of adult victims • Establish amount of semen present • Graded on a scale • Expectation on time taken for semen to ‘drain’ from body • Semen will drain from the vagina, accelerated by – Washing – Menstruation – Physical activity NOT PROTECTIVELY MARKED

Sex offences – Time since intercourse • Sperm expected in vagina for up to 3 days but can be found up to 7 • AP present for 1 to 2 days, sometimes 3 day • Semen on mouth and anal swabs less persistent (2 and 3 days) • Skin/nails dependent on washing/abrasion • Opinion on TSI in court – e. g Angelika Kluk murder

Sex offence cases – other considerations • If intimate swab are negative or not available • Complainer’s underwear– ‘drainage’ stain • Penile swabs – DNA transfer • Accused’s clothing – DNA transfer

Sex offences – Other considerations Non- intimate swabs; Biting/licking/blood – e. g. saliva inside top ‘Grab’/Damaged areas – contact skin/clothing Finger nail scrapings washed clothing – bulk extractions Limitations – when known to each other, social contact - clothing being washed together (sperm cells)

Visible staining – Other body fluid tests • Urine • Saliva – screen and tube • Faecal material • No test specific for vaginal material

Body Fluid Identification - Saliva Presumptive testing Screen and tube test Limitations: False positives (body swabs) False negative (non secretors) NOT PROTECTIVELY MARKED

Saliva and sex offence cases • case example – forced oral sex on a 12 year old boy • Suspect is an older male • Perfomed oral sex on the complainer for approx. 30 s before the complainer managed to break free • Penile swabs taken approx. 18. 5 • Mixed profile – allow for complainer • Inside boxer shorts – phadebas positive • Even mix of DNA from suspect and complainer • DNA amount and phadebas, report as saliva • Supports victims acount NOT PROTECTIVELY MARKED

Sexual Offences DNA - differential extractions • Creating DNA profile from sperm DNA and ‘non sperm’ DNA • Recover DNA from both suspect and victim • ‘Drainage’ stains at crime scenes or saliva/semen mixtures e. g carpets, bedding NOT PROTECTIVELY MARKED

Globalfiler and Sex offences • Went live in 2014/2015 • increase in sensitivity • increase in profile complexity • Increased discrimination NOT PROTECTIVELY MARKED

DNA profiling – Globalfiler or ‘DNA 24’ • SGM+ markers retained in new kit • 11 new markers, 21 in total • 2 new sex markers 3 in total • More information per profile NOT PROTECTIVELY MARKED

Globalfiler – greater sensitivity = challenge Increased sensitivity presents challenges as well as opportunities. Greater risk of contamination being detected. Preventative measures become even more important. • PPE when handling items and during medical exams • Different medical rooms – thoroughly cleaned between • Different doctors (or separated by time and barrier clothing worn)

Global filer – increased sensitivity – Sex Offence case • Case background at approx 6. 30 am on 27 July 2014 male attended at 91 year old victim’s H/A • He punched her to the face, knocked her to the ground and had vaginal sexual intercourse with her • Victim scratched the assailant NOT PROTECTIVELY MARKED

Global filer – increased sensitivity • Complainer was medically examined approx. 6 hours after the incident due to her distress limited swabs taken • A woman appeared at police cordon suggesting to police they were looking for her son • 17 year old accused was medically examined approx. 6 hours after the incident • Locus examination was negative NOT PROTECTIVELY MARKED

Global filer • Initial results; • • Blood on accused’s clothing matches the complainer Complainer’s swabs negative Accused’s penile swabs negative The inside of the accused’s boxer shorts were sampled for DNA • SGM+ result – 4 types extra types, all matched complainer • Statistic of 1 in 150 • Accused denied sexual contact but admited robbery NOT PROTECTIVELY MARKED

Global filer • Sample from inside the accused’s boxer shorts was re-worked • DNA matching the accused plus 18 other types • All present in profile of the complainer • Statistic of 1 in more than 1 billion • DNA matching the accused was detected on the fingernails NOT PROTECTIVELY MARKED

Global filer • On the strength of the evidence from the boxer shorts and fingernail scrapings from complainer • Accused pled guilty to sexual offence • Sentenced to 12 years and supervised for 7 years after release Judge commented “cruel and degrading attack” NOT PROTECTIVELY MARKED

Case Study 2 – Global filer sensitivity • Family friend looking after 3 year old boy • Victim alleges the suspect has put his “pecker” in his mouth • Medical exam approx. 10 hours later • Oral rinse = negative for semen • Peri oral swab = traces of semen (differential extraction) • DNA profile matches suspect NOT PROTECTIVELY MARKED

Case Examples – Washed Items • Suspect is the father of the complainer’s friend • Allegation of oral rape with ejaculation onto her face • Wipes face with t-shirt • Specific area targeted • Traces of sperm detected • Male DNA profile obtained

Case Examples – Washed Items - contamination • Female complainer reports having been raped by a friend of her brother. • Pants examined and DNA with a profile matching that of her brother was obtained from sperm heads. NOT PROTECTIVELY MARKED

Specialists DNA Tests • Y-STR profiling techniques • STR mix • LMD targeted DNA sampling NOT PROTECTIVELY MARKED

• Allows for analysis of small amounts of male DNA, without masking by female DNA - unlike GF • No database therefore requires reference • Same profile through out males in family, stat not as good(10, 000 s) • Multiple males present • Azoospermic semen • Digital penetration/no ejaculation • Swabs negative for sperm in one study, 29% of these gave a Y-STR profile NOT PROTECTIVELY MARKED

Recent developments – STR mix • New DNA interpretation software • Allows interpretation of complex mixed DNA profiles that we couldn’t do previously NOT PROTECTIVELY MARKED

Laser micro dissection Laser beam pulse Eppendorf tube NOT PROTECTIVELY MARKED

Applications of LMD • Allows selection of particular cell for DNA analysis • 10 cells for diploids • Currently establishing number sperm cells (haploids) • Cold cases – selecting sperm cells from slides • Live cases – targeting trace amounts of sperm cells • Fluorescence capability NOT PROTECTIVELY MARKED

Useful Resources • SPA staff on call for queries / advice • Carol. rogers@spa. pnn. police. uk • 01236 818286 NOT PROTECTIVELY MARKED

ANY QUESTIONS? NOT PROTECTIVELY MARKED