Morphology of drying blood pools

Nick Laan (1) , Fiona Smith (2) , Celine Nicloux (2) , David Brutin (2)

1 IRCGN - Institut de Recherche Criminelle de la Gendarmerie Nationale
2 IUSTI - Institut universitaire des systèmes thermiques industriels

Often blood pools are found on crime scenes which may provide information concerning the events that took place on the scene. However, there is a lack of knowledge concerning the drying dynamics of blood pools. This study focuses on the drying process of blood pools to determine what relevant information can be obtained for the forensic application. We recorded the drying process of blood pools with a camera while measuring the mass. We found that the drying process can be separated into five different stages: coagulation, gelation, rim desiccation, centre desiccation, and final desiccation. Moreover, by normalizing the mass and drying time we show that the mass of the blood pools diminish similarly and in a reproducible way for blood pools created under various conditions. In addition, we verify that the size of the blood pools is directly related to its volume and the wettability of the surface. Our study clearly shows that blood pools dry in a reproducible fashion. This preliminary work highlights the difficult task that represents blood pool analysis in forensic investigations, and how internal and external parameters influence its dynamics. We conclude that understanding the drying process dynamics would be advancement in time line reconstitution of events.

Domaines: Milieux fluides et réactifs; Biomécanique [physics.med-ph]; Mécanique des fluides [physics.class-ph]; Thermique [physics.class-ph]

Nick Laan, Fiona Smith, Celine Nicloux, David Brutin. Morphology of drying blood pools. Forensic Science International, 2016, 267, pp.104-109. ⟨10.1016/j.forsciint.2016.08.005⟩. ⟨hal-01770001⟩