Volume 23, Issue 4 (October 1978)
Identification of Burnt Matches by Scanning Electron Microscopy
An arson case recently investigated in our laboratory started the work reported in this paper. A fire broke out in one of the detention ceils at the Stockholm police headquarters. The fire was restricted to a plastic board mounted on the wall of a high security cell. During the investigation of the cause of the fire several small fragments of some burnt material were found in one of the small holes in the board. These were sent to the National Laboratory of Forensic Science (NLFS). The fragments were examined in a light microscope. The dimensions, the cross sections, and the fiber structures resembled those of burnt matches. The investigation was continued in the scanning electron microscope (SEM). Morphological observation showed very good agreement between burnt matches and the examined fragments. A small amount of nonfibrous substance was observed at the edge of one of the fragments. With energy dispersive X-ray analysis (Fig. 1a) the following elements were detected: chlorine, potassium, silicon, aluminum, sulfur, phosphorus, iron, manganese, chromium, zinc, and magnesium. The same elemental composition was found for the burnt heads of the most common match in Sweden (brown head, Svenska Tändsticks AB). A typical analysis is shown in Fig. 1b. Furthermore, the elemental composition of the suspect fragments agreed with that of the wood from burnt matches (Fig. 2). The strong phosphorus signal originates from additives to the matchsticks. The phosphorns signal in Fig. 1a stems presumably from the same source.