"The autopsy revealed that Sicknick, 42, said the strokes at the base of the brain stem were caused by a blood clot, Chief Medical Examiner Francisco Diaz said. The formal finding was that the death was caused by "acute brainstem and cerebellar infarcts due to acute basilar artery thrombosis" and that the manner of death was "natural." Diaz told The Washington Post that the autopsy found no evidence that Sicknick experienced an allergic reaction to chemical irritants. He also said there was no evidence of either external or internal injuries."