Blood pattern analysis - BPA - and interpretation from Forensic Access: independent forensic scientists

Blood Pattern Analysis (BPA) and Interpretation

Blood pattern analysis (BPA) is routinely carried out at the scenes of violent crime (murder, rape, etc.) and on clothing when blood has been shed.

Forensic Scientists trained in blood pattern analysis can gain a wealth of information by a detailed study of bloodstain patterns. The distribution, size and shape of bloodstains on a victim, on a suspect or at a crime scene can be useful in the interpretation and the reconstruction of the events causing the blood pattern found.

Forensic Scientists are interested in blood distribution in cases of assault, for instance in an alleged kicking case; the distribution and nature of blood on footwear is important for the interpretation.

Forensic Access scientists are highly trained and experienced in the detection and interpretation of blood stain patterns. They can be called upon to examine or re-examine scenes of crime and/or visit other forensic laboratories to examine or re-examine clothing in a criminal investigation, where BPA has been used by the prosecution or is suspected to exist, but not yet been analysed.

Our forensic scientists have extensive laboratory and crime scene experience and recognise the importance of carrying out experiments to support their evidential findings.

From the defence angle, our forensic scientists can help to evaluate blood pattern analysis evidence produced by the prosecution. We can, for example:

re-examine exhibits previously examined by the prosecution, looking for blood not previously found and to ensure that there has been no other evidence type missed;
examine the blood patterns found and interpreted by the prosecution and test the hypotheses produced. Is there an alternative and realistic scenario of how these blood patterns were produced?
check that the procedure used to examine the exhibits and the BPA itself were in compliance with the laboratory’s stated, quality management procedures;
check to see if their has been any chance of contamination of the items;
discuss the interpretation of the blood pattern analysis with the prosecution scientist, exploring weaknesses and strengths of the interpretation;
check and assess the credibility of the prosecution's BPA expert witness – being competent in blood pattern analysis takes many years of training and the person must be a very experienced forensic scientist to make these analyses and interpretations;
look for and explore realistic and viable alternatives to the interpretation of evidence and the translation of that into how/when the event occurred and how the blood patterns were produced;
produce a detailed report of the findings including photographs and diagrams where appropriate.