Question about a raid hack?

My guild started a heroic rancor raid and a level 73 player with just mace windu as his only 7 star posted 2.7 million damage. Is there a way the credit can be accidently given to another player because their GP is 250k and this just isn't possible to do that damage at his level/gear. If not then I am ready to accuse this person of hacking. Looking for info.