A study of mosquito-coils as timing devices in an arson crime

Several arson cases in which mosquito-coils were used as timing devices occurred recently in Fukuoka prefecture. We investigated the method of ignition and components to distinguish 5 maker's mosquito-coils. As the result, it cleared that the mosquito-coil itself was not able to set fire to papers or cloths containing kerosene or gasoline. A small amount of gunpowder, a sparkler or a few matchsticks were required. Five maker's mosquito-coils were successfully distinguished using thin layer chromatography or gas chromatography-mass spectrometry. The obtained results should be useful as reference data in practical arson crimes.