Sudden deaths due to natural causes are commonly seen in forensic practice, most of which are attributed to cardiovascular diseases. Cardiac tamponade (CT) is one of the causes of sudden cardiac death, with a fatal outcome usually detected at autopsy. While both trauma and non-traumatic causes are responsible for CT, it is a known complication of acute myocardial infarction leading to cardiac rupture that involves the ventricular wall, septum, and papillary muscles. We report the case of a 50-year-old male who collapsed suddenly and was declared dead in the Trauma and Emergency Unit of the hospital before admission. Autopsy findings revealed 250 mL of blood and a 206 g blood clot in the pericardial cavity with a vertical tear on the posterolateral surface of the left ventricle with focal hemorrhagic myocardium consistent with acute myocardial infarction. The cause of death was CT as a result of myocardial rupture due to acute myocardial infarction. The gross and histopathological findings were diagnostic and revealed thrombosis of the left circumflex artery, transmural myocardial infarction, and ruptured myocardium of the left ventricle.