In some cases, it is difficult to determine a single cause of death even after conducting full autopsy and additional tests. A 49-year-old man, reportedly having diabetes mellitus, was found unconscious by his mother and revealed to be dead. He had several contusions all over his body, including the right periocular area, but they did not appear fatal. A focal area of polymicrogyria and cortical dysplasia was found on the right preoccipital notch, accompanied with dystrophic calcification and leptomeningeal angiomatosis. These findings were considered indicative of Sturge-Weber syndrome, a rare neurocutaneous disorder, of atypical type without facial lesions. Blood level of β -hydroxybutyrate was 859 μ g/mL, implying that he also had diabetic ketoacidosis. His ketoacidosis may not have been corrected appropriately because of status epilepticus in association with brain lesion, resulting in his death, but neither direct evidence nor statement was obtained. In cases with several apparent causes of death, the examiner's assumption should be based not on imagination but on evidence, and logic should not be overlooked. It is more helpful for the investigators or the bereaved to obtain more detailed information rather than come to a hasty conclusion.