The murder of Tracy Wylde – a cold case review and ethnicity profiling
Dr Nighean Stevenson, Forensic Scientist, Biology/DNA, Scottish Police Authority
Tracy Wylde was 21 when she was murdered in Glasgow in 1997. She had been manually strangled. As a
known sex worker, her murder took place at a time when a number of women who worked in the sex
industry had been murdered in the Glasgow area, sparking fears that prostitutes were being targeted by a
serial killer. In 1997, using SGM™ profiling, an unknown male DNA profile was detected from a stain on Tracy
Wylde’s trousers and on her fingernails. However, no matching DNA profiles were found on the Scottish or
UK National DNA Database. Neither was the unknown DNA profile identified through mass screening, familial
searching or searching international DNA Databases over the subsequent 20 years. Over the course of several
cold case reviews, this DNA profile was ultimately upgraded in 2015 using the GlobalFiler™ (DNA24). The
increased sensitivity of this kit allowed us to identify trace DNA on various locations of the deceased’s body,
including her neck and a bite mark, inferring that this unknown male was the likely perpetrator of the
murder. Various unusual DNA markers were present in this GlobalFiler™ DNA profile, and we were able to
provide the investigating team with the likely ethnicity of this unknown male.
In 2018 a match was finally obtained on the Scottish DNA Database and a male, who matched the ethnicity
profiling data, was arrested for the murder of Tracy Wylde. This case study shows the impact of improving
DNA profiling technologies as a powerful tool to infer ethnicity and its potential usefulness to investigating
officers in both cold and live casework.
Nighean has worked as a Forensic Scientist in Biology/DNA for the Scottish Police Authority for 18 years.
During this time she has worked on a number of high profile murder cases (both live and unresolved), sexual
offence cases and large scale drugs operations. Prior to becoming a Forensic Scientist, she worked in Cancer
Research and Genetics for 8 years.