Waco investigation: analysis of FLIR videotapes

This paper presents some of the image processing techniques that were applied to seek an answer to the question whether agents of the Federal Bureau of Investigation (FBI) directed gunfired against the Branch Davidian complex in the tragic event that took place in Waco, Texas, U.S., 1993. The task for this investigation was to provide a scientific opinion that clarified the cause of the questioned events, or flashes, that can be seen on one of the surveillance videotapes. These flashes were by several experts, concluded to be evidence of gunfire. However, there were many reasons to question the correctness of that conclusion, such as the fact that some of the flashes appeared on a regular basis. The main hypothesis for this work was that the flashes instead were caused by specular solar reflections. The technical approach for this work was to analyze and compare the flashes appearance. By reconstructing the spatial and temporal position of the sensor, the complex and the sun, the geometrical properties was compared to the theoretical appearance of specular solar reflections. The result showed that the flashes seen on the FLIR videotape, were caused by solar or heat reflections from single or multiple objects. Consequently, they could not form evidence of gunfire. Further, the result highlights the importance of considering the characteristics of the imaging system within investigations that utilizes images as information source. This is due to the need of separating real data from other phenomena (such as solar reflections), distortions and artifacts in a correct manner.