A 65-year-old man collapsed suddenly, while on an escalator. Despite intensive cardio-pulmonary resuscitation, the subject died 1. h later. Post-mortem magnetic resonance imaging and post-mortem computed tomography angiography demonstrated rupture of an ascending aortic aneurysm, with haemorrhage into the pericardial cavity and the uncommon associated finding of haemorrhage into the left hemi-thorax through a small left-sided pericardial defect. The cause of death was thus attributed to the rupture of thoracic aortic aneurysm, and traditional autopsy was not performed. The circumstances of the case will be discussed, followed by a discussion of the imaging findings, mechanism of death, and explanation of the findings in this case. Finally, on the basis of this case report, we suggest that in selected cases, post-mortem imaging can be used as a screening tool for conducting hypotheses on the cause and mechanism of death before autopsy.