Forensic medical cytological examination of the trace evidence on the knife’s blade in the case of multiple penetrating stab/cut wounds in the chest with lung damage: a case report

Various trace evidence are often found on the instruments of mechanical injury, including microparticles of human’s damaged organs and tissues. The detection of cells and microparticles of organs and tissues on the instrument of injury confirms its contact with the human body, which is of great evidentiary value.

The article presents the results of forensic medical cytological examination of biological evidence taken from the knife’s blade in the case of multiple penetrating stab/cut wounds in the chest that result in lung damage. Microscopic preparations were made from the traces on knife’s blade, which were stained with fluorochrome solutions (0.0005% aqueous solution of atebrine and 0.01% solution of acridine orange). The study was performed using the luminescent microscope Leica DM2500 (20× and 60× lenses, 10× eyepiece). The examination of microparticles of the striated skeletal muscle revealed areolar connective and fat tissues with capillary and arteriole fragments. The isolated mesothelial cells and type II pneumonocytes were also detected. Fibers of the striated skeletal muscle tissue looked like long multinucleated cells with distinguishing cross-striation. The areolar connective tissue was represented by loosely arranged fibers embedded in the ground substance. Fragments of the fat tissue looked like the clusters of round and oval large cells, tightly pressed together, with capillaries, and arterioles in between. Y-chromatin was detected in the nuclei of most cells. In addition, human blood was found on the knife’s blade.

Thus, the study revealed that tiny particles of tissues and isolated human cells of the male genetic sex were detected, their organ–tissue affiliation was established, which is a valuable diagnostic finding, because it confirms the contact of the trauma instrument with the human body.