Expertises médico-légales - La morphoanalyse des traces de sang

The bloodstain pattern analysis is the forensic science discipline consisting of the examination and distribution of blood traces to determine the mechanism causing them.

This discipline has been available at IGNA since September 2008. After the first works of Dr. PIOTROWSKI in 1895 on the principles of this field, it begins to develop in the 1950's in the United States (Dr. SHEPPARD vs. the State of OHIO trial) until the International Association of Bloodstain Pattern Analysts (I.A.B.P.A.) is set up in 1983, of which each morphologist in our laboratory is a member.

The objective of these tests is to reconstruct the facts, to localise them. It also allows for the verification of the compatibility of the evidence.

Thus the bloodstain pattern analysis allows one to determine :

• The most probable scenarios of bloody crimes:
• The minimum number of blows during the events.
• The type of weapon used.
• The location of the injury(ies) (the origin of projectiles).
• The approximate position of the victim and/or the perpetrator.
The bloodstain pattern analysis, linked to the autopsy report, places the subject during the violent bloody events of which he or she was a victim.


• Chronology of facts.


• The compatibility of evidence with the blood traces found..

This discipline is based on the following test principles :
• Research on blood traces: :
  Probing observation (visible traces), complemented by chemical detection (latent traces).
• Analysis of the shape and distribution of blood traces :
  Determining the mechanisms causing the traces observed and/or detected.
• Graphic and trigonometric test of blood traces:
  Placing different participants when there are spatters following an impact.
• Analysis of the general distribution of blood traces: :
  Determining the most probable hypotheses regarding the bloody acts and the course of events.

As a complementary analysis to genetic tests, the bloodstain pattern analysis also allows an objective choice of the traces to be collected for this type of analysis.

It may be of interest to you that IGNA offers bloodstain pattern analysis at all of its sites. In fact, the DNA and fingerprint expertise provides information regarding the participants of an event, whereas the bloodstain pattern analysis reveals the elements regarding the course of events.

All of our technicians are trained to examine the samples according to the principles set out for bloodstain pattern analysis. Moreover, an expert or an expert assistant can at any time be consulted when a sample is examined so as to ensure that the best choices are made.

The examination of samples following the rules of bloodstain pattern analysis allows us to accurately determine which traces should be collected to enable us to answer any questions that you may have. When discussing objective sampling, this will be in the sense of a reduction in the number of samples to be carried out and thus incurring a reduction in costs.

The combination and the analysis of all the expertise on the same record result in a comprehensive description of the crime scene. .

Due to the training in forensic science (DESS [Diplôme d'Etudes Supérieures Spécialisées - Diploma of Specialized Graduate Studies]), our expert in bloodstain pattern analysis also has the expertise to conduct analyses of all the instruction items, as well as a synthesis of all the expertise conducted on the same event.