The analysis of the stomach contents did not detect the presence of diazinon itself, but several decomposition products of diazinon were detected, notably monothiono-TEPP, which is much more toxic than diazinon itself. The most abundant components in the stomach samples were 6,6'-thiobis (2-isopropyl-4-methylpyrimidine) and 2-isopropyl-4-ethylthio-6-methylpyrimidine, which are known characteristic degradation products of diazinon. The detection of these various components in the stomach of the deceased provided persuasive evidence that the victim drank decomposed diazinon. Although diazinon is considered to be relatively stable under normal conditions, it often undergoes self-decomposition during storage for unknown reasons. The constituents of the liquid sample were detected in the stomach contents by the use of conventional forensic analytical methods, namely, thin-layer chromatography and gas chromatography-mass spectrometry. The description of the materials and methods used includes the specifications of the apparatus used and analytical conditions. 7 figures, 2 tables, and 11 references