Evaluating the impact of DNA evidence in cold cases. Can this lead to a successful conviction in time?

What is DNA?

Friedrich Miescher (1869): first identified and isolated DNA, first calling it ‘nuclien’ Rosalind franklin and Maurice Wilkins (early 1950s): took the first x-ray photo of DNA (photograph 51) showing its double helix, shape and dimensions James Watson and Francis Crick (1953): built models of the double helix, explained how it could carry genetic information Deoxyribonucleic acid (DNA) is made up of many bases linked together using a phosphate bond There are two strands to each DNA which form a double helix DNA can be found in every cell in the body The places of the bases in the DNA are individual to each person

DNA in criminal forensics

Sir Alec Jeffreys discovered DNA fingerprinting in 1984 Was first used in 1986 to let a suspect go and fine the real killer in the pitchfork murder case As DNA evidence is scientifically respected it holds a lot of power in the court room, meaning that if a new piece of DNA evidence is found a suspect can be released or convicted instantly.

Criminal justice system

"There has been an increase in convictions as a result of DNA" (Appendix 1) Used to solve cold cases New DNA evidence has led to exonerate suspects DNA evidence is shown to be the most reliable evidence as it is the most conclusive and scientific evidence Before 1985 time to find a suspect and convict them was much greater than after DNA was introduced

Use of DNA in forensics

Without forensic evidence 24% of crimes would be difficult or impossible to detect Suspects were found 45% of the time through the national DNA database (NDNAD) using DNA matches DNA evidence has yielded the wrong suspect in only 3% of serious crime and 1% of volume crime Cases involving scientific analysis were 3 times more likely to be cleared by police

Future developments

Forensic scientists in the future could go on to analyse someone’s entire genome (their complete set of DNA) it may be possible in the future to predict eye colour, race, sex or even facial features just from a DNA sample

How is DNA collected, stored and extracted?

DNA samples can be anything from blood, semen, saliva, urine, feces, hair, teeth, bone, tissue and cells Best DNA evidence is from samples found where they weren’t supposed to be like a hat from a breaking and entering Elimination samples are also taken form consensual sex partners and other (first responder, CSI, analyst working the case) Extraction is the process of releasing the DNA from the cell Quantitation is the process of determining how much DNA you have Amplification is the process of producing multiple copies of the DNA in order to characterize it Separation is the process of separating amplified DNA product to permit subsequent identification Analysis & Interpretation is the process of quantitatively and qualitatively comparing DNA evidence samples to known DNA profiles Quality Assurance is the process of reviewing analyst reports for technical accuracy

How is it used in cold cases?

Night stalker- Delroy Grant

• Convicted of 29 charges • 1992-2009 • Committed a series of burglaries and sexual assaults against elderly victims in south-east London between • Traditional methods of investigation failed to identify suspect, so the case went cold multiple times • DNA gathered at the crime scene did not match NDNAD • Tried ancestral DNA profiling and the ethnicity was discovered • Launched an operation called Minstead • Hundreds of men in London had to give DNA samples most of which were black • A DNA sample taken from the victim finally identified him • Semen samples from victims were taken but none of which linked to a suspect • Expansion of the NDNAD resulted in a suspect being found and allowed the police to find the suspect • The carful extraction of the semen samples and the preservation of them resulted in them being able to be used in the future • Grants DNA was added to the database because of an unrelated arrest which led to a direct match • DNA also allows to link different crimes to one offender • Allowed to see the scale of his attacks and led to life in prison

• Grants DNA was not used effectively even though they had it for since 1992 which shows DNAs dependence on the NDNAD • Over 2,000 samples of DNA were collected from suspects from 1992 to 2009 • Without unrelated arrest the DNA samples would still be unusable • This resulted in him being able to offend for much longer • Police still used traditional policing methods and didn’t just rely on DNA • Operation Minstead cause a lot of controversy as people called it an abuse of power and that it damaged the relationship between black people and the police • It also wasn’t as successful as hoped because they were able to reduce the number of suspects from 21,000 to 1,000 but didn’t find the suspect

The Cromwell Street murders-

• Frederick West and Rosemary West • 1967- 1987 • When bodies were discovered at 25 Cromwell Street in 1994 many of them were decades old and cold cases • DNA helped identify the victims • As most of the bodies where heavily decayed after such a long-time visual identification was not a viable way of identifying them • Led to the positive identification of Heather West, their daughter • As DNA evidence was used to identify victims it played a large part in the conviction • Fred Wests confession and witness testimony was backed up by the DNA evidence making it more reliable • The historical investigative standards limited the ability to use DNA as most of it was poorly preserved

The pitchfork murder- Colin Pitchfork

• Sentenced to life in prison • 1983-1986 • Arrested in 1988 after pleading guilty for both murders • Murdered and raped Lynda Mann and Dawn Ashworth • DNA evidence of semen taken from Lynda Mann