Answer
The Assyrian king Sargon II was killed by an Elamite ambush in 705 BCE. His body was not retrieved, and his death was not publicly announced for months. This may have been due to a political power struggle, as Sargon's son Sennacherib was not the immediate heir to the throne. Sennacherib eventually became king, and he avenged his father's death by conquering Elam in 691 BCE.