Daniel Bonn to start on CSI valorisation project
The FOM Foundation has awarded a valorisation grant to Prof. Daniel Bonn. He will use his expertise in the area of fluid dynamics to investigate blood drops. The aim of the research is to determine precisely where the blood spatters at a crime scene originate from based on their shape. Bonn will collaborate in this project with Dr. Karla de Bruin from the Netherlands Forensic Institute (NFI) and E-Semble, a software company that can produce simulations of blood drop trajectories.
If a crime is committed then six questions must be answered: Who? What? Where? When? Why? And How? The so-called Bloodstain Pattern Analysis (BPA), which Bonn seeks to improve with his research, concerns what happened and where exactly that occurred. Who did it can be investigated using DNA or fingerprints, for example.
Accurate calculation
The current calculation method for determining the origin of blood assumes that the blood moves in a straight line. Yet in reality, the trajectory is bent due to gravity and air resistance. NFI recently demonstrated that if investigators use the conventional method to determine the source, based on a bloodstain pattern on a wall, then their answer can be up to 44 cm off the mark. That is more than the difference in height between a sitting and a standing person. However, an accurate calculation of the victim's position can provide a lead in the investigation: is it a murder or a case of self-defence?
Fundamental research
Reconstructing the trajectory of a drop using the software requires three pieces of data: the angle at which the blood drops hit the wall, the volume of the drops, and their speed. The angle can be derived from the ratio between the height and width of a blood spatter. This is done already. Bonn will concentrate on the other two variables and in doing this will make use of fundamental research in the field of fluid dynamics.
Objectivity
The project can contribute to the Bloodstain Pattern Analysis in various ways. First of all, use of the software programme will make the investigation more objective. Furthermore, the position of the victim can be calculated far more accurately and the position of the crime can be viewed in 3D. And because more variables are calculated, both blood spatters that travelled upwards and those that travelled downwards can be analysed. The current method is only suitable for spatters that moved upwards. Last but not least, the investigation will take far less time using this software.
Contact
Daniel Bonn (Van der Waals-Zeeman Institute, University of Amsterdam)
Further information about valorisation at FOM can be found on the FOM website.