This paper presents an algorithm for ellipse detection on stains of blood, which is directly suited for the needs of forensic analysis. The algorithm is of the edge-analyzing type. It performs convexity detection and is able to split contours of overlapping ellipses by concave regions analysis. A filtering is applied to the fit ellipses to reduce the results only to those results necessary for blood drop trajectory tracing. Results for running time and fitting quality tests performed on real-life and artificial data are presented. The solution answers to both quality and running time expectations of the field of application.