Simplify the following text for a Grade 9 native English-speaking person.
Original: His body was found interred under the ashes of the Vesuvius with no apparent injuries on 26 August , after the plume had dispersed , confirming asphyxiation or poisoning .
Simplified: His body was found buried under the ashes of the Vesuvius with no apparent injuries on 26 August , after the plume had dispersed . This confirmed the death through asphyxiation or poisoning .