Examining Exhibits from the past in the harsh light of the present
Dr Martina McBride Director of Science and Development, Forensic Science Ireland
One of the biggest challenges in Forensic analysis of cold cases is the issue of contamination of the exhibits.
Often these exhibits were previously examined in an era where you needed a large stain to get a DNA profile
so contamination was not an issue in the same way as it is today when we are looking for minute traces of
DNA, sometimes not associated with a stain. This issue will be addressed using the example of the
Grangegorman murders where Mark Nash was convicted in 2015 of a double murder committed in 1997. The
conviction hinged on DNA profiles matching both victims on samples taken from his jacket. The Forensic
Evidence was vigorously challenged in court at the time on the grounds of cross contamination but was
ultimately accepted and Mark Nash was convicted.
Martina McBride is Director of Science and Development in Forensic Science Ireland. She worked as a
Forensic Biologist and then in the DNA area. She worked in and managed Sexual assault, Volume crime and
Serious crime teams. She was also manager of the Chemistry Section for 2 years. She has been involved in
and given evidence in many high profile cases through the years including cold cases. In the past she has
been a member and the Chairperson of the Body Fluid Forum (BFF), and is a member of the European
network of Forensic Science (ENFSI) Research and Development group. She was appointed as Director of
Science and Development in FSI in 2019. She is responsible for accreditation and quality and her role also
involves driving innovation and research and development in FSI.