The name of this Osorkon in the Amarna Letters was in fact Mut-Baal, "Man of Baal". The attack on the priests of Baal was of course related to the political/royal struggle going on at the time (rather than being a purely religious dispute), but it doesn't seem that Osorkon was assassinated at that exact same time. He went down in a separate incident at a different location, and perhaps as much as a year earlier, at least according to the Kings/Chronicles reckoning. However, the hit-man was the same in both events, Jehu.
© Charles N. Pope, US Library of Congress. All rights reserved.