The remains of the sign shop building showed that the point of origin was in a trash can located in the building. Samples of items in the trash can and in the immediate area were collected and tested, and the tests were negative for any type of accelerant. There were no electrical lines or other sources of ignition in the immediate area, and it was too short of a time span to have been caused by a discarded cigarette. It was ruled that some person unknown had started the fire in the area of the waste basket, and that the person had intentionally set the fire with some source of open flame (such as a match).