Needles in Haystacks

Transcription

1 Human Identification Solutions (HIDS) Conference Madrid 2-4 March 2015 Needles in Haystacks - Finding DNA traces to test in complex historic cases Professor Angela Gallop 4 March 2015

2 My talk today Historic cases and additional challenges they present Five of the UK s most complex and high profile cases and how they were solved Lessons learned from each for the future Particularly in relation to finding DNA traces to test And ensuring quality and relevance of the results

3 Extra challenges with cold cases Finding things to test Nature and condition of things when they are found Discovering what original tests covered and detail of results Shortcomings in Continuity and Integrity Getting free enough rein Explaining why evidence originally missed Admin Scientific documentation

4 Cardiff prostitute what happened Vicious knife attack on young prostitute in Cardiff in 1989 Over 50 stab cuts, slit throat and cut wrists Foreign blood identified at crime scene Said to match a female witness 1992 false confessions led to conviction of The Cardiff Three Released on Appeal - 2 years later Successive subsequent attempts to obtain DNA profile from remains of the foreign blood all failed

5 Cardiff prostitute how it was solved Developed full understanding of sequence of events from blood patterns etc Focused on the foreign blood Unearthed new samples to test Obtained full DNA profile forming a pattern on and around the body No match on DNA Database but manual search identified 14 year old boy as of interest Profiled his family members until found an uncle whose DNA matched

6 Cardiff prostitute - lessons learnt Make sure you really understand the crime scene Be persistent in locating for items to test Be imaginative about what to test Don t put things in the too difficult box Leave unsolved case files in good order

7 Young black boy what happened Young black boy stabbed in leg with broken bottle in 2000 In stairwell of block of flats in London Suspect brothers arrested 5 days later No forensic evidence found 2002 failed prosecution of 4 others No forensic evidence on them either 2002 Metropolitan Police commissioned independent review of its performance

8 Young black boy how it was solved Re-examined items from all previous suspects Revealed blood on clothes of both suspect brothers Including 9mm stain on trainer DNA in blood matched boy s Textile fibre embedded in blood matched his jumper fibres Other fibre links found but risk of cross contamination

9 Young black boy - lessons learned Don t make assumptions about previous work Even if conducted by well trained scientists working in quality assured and accredited environment Don t let DNA blind you to other evidence Check for obvious potential contamination routes at an early stage Don t get caught up in any blame game about previous investigations

10 Young mother what happened Young mother stabbed to death on Wimbledon Common in front of young son in 1992 Lower clothing pulled down to expose intimate areas of body 1993 suspect S. charged with murder 1994 suspect S. cleared after honey trap exposed

11 Young mother how it was solved Examined items from victim - included body taping on which no DNA originally detected Re-testing revealed victim s DNA and hint of male DNA Developed new enhancement technique to improve results Combined with other DNA techniques Identified serial rapist and murderer suspect N. Further links involved: Paint matching N. s tool box Footwear mark at scene

12 Young mother - lessons learned Be watchful for dogs that don t bark Consider ramifications for other cases Operation Cube Develop new techniques when you need to even if these take some time Complete their validation at the time Trust your common sense and experiment

13 Coastal Path Murders what happened Couple shot at close range on coastal path in 1989 Bodies hidden in undergrowth 2006 suspicions emerge about convicted serial thief and armed robber, suspect C. And potential links with murder of two other people and multiple rape/sexual assault at gunpoint Clothing and jewellery in local hedgerows

14 Coastal Path Murders how they were solved Started with unsuccessful search for foreign DNA on victims, then switched to textile fibres Found matches between fibres on victims and glove in hedgerow Then myriad of other fibre links between victims, suspect C. s home and hedgerow And then fibre links with the two other victims and sex assault cases Victim s blood on gun linked to suspect C. Then victim s blood on suspect C. s shorts Then victim s daughter s blood on suspect C. s shorts!!!

15 Summary of forensic evidence

16 Coastal Path - lessons learned Beware of DNA straightjackets Other evidence can guide you to DNA And enrich your understanding of the crime and a suspect s likely involvement Balance close working relationships with police and independence Accept truth is sometimes stranger than fiction Don t be put off if prosecutors find evidence inconvenient

17 Black teenager what happened Young black teenager stabbed to death in London in 1993 by gang of white youths Suspects identified after 2 weeks Failed private prosecution in 1996 Independent Police inquiry for IPCC Public Inquiry in 1998/9 Metropolitan Police described as institutionally racist Continuing investigation including forensic science 2004 Crown Prosecution Service says insufficient evidence to prosecute 2005 double jeopardy scrapped

18 Black teenager how it was solved Noticed red fibres on victim s clothing which could have come from own shirt Found 2 types of similar fibres on suspects D. and N. Then found 2 more fibre types on them matching other items of victim s clothing And then blood in packaging of suspect D. s jacket containing 5 th matching fibre type Then found blood on the jacket itself Found hair matching victim s on suspect N. s jeans Investigated potential for results due to cross contamination

19 Summary of forensic evidence Suspect N. Suspect D.

20 Black teenager - lessons learned Don t make assumptions about loss of evidence with time Don t focus just on outer clothing for transferrable traces Take debris inside packaging very seriously Recognise evidence can be missed however diligent and quality controlled the search Focus investigations into potential for contamination to make them manageable

21 Investigating Historic Contamination Availability and Opportunity Use a separate scientist working independently Take each strand of evidence and Explore its history since seizure of the relevant item And the history of the potential source of evidence Work out the nature and number of transfer steps required for unwittingly transfer of the evidence And likelihood of each of these steps occurring To estimate overall likelihood of contamination as explanation for the evidence Sitting in court to listen to relevant evidence

22 Critical success factors Challenge historic expectations Don t make assumptions about previous work Always start at the crime scene however long ago Be imaginative about searching for things to test Be tenacious about finding them If you find 1 type of evidence, there may well be others Beware of the too difficult box When things don t stack up, find out why Recognise when you re on to something and look deeper Keep inventing new techniques and approaches Make sure they are covered within your quality management system Recognise truth is sometimes stranger than fiction Explore potential for alternative explanations involving contamination

23 Those who cannot remember the past are condemned to repeat it George Santayana

24 Human Identification Solutions (HIDS) Conference Madrid 2-4 March 2015 Needles in Haystacks - Finding DNA traces to test in complex historic cases Professor Angela Gallop 4 March 2015

25 Speaker was provided travel and hotel support by Thermo Fisher Scientific for this presentation, but no remuneration.