You're under investigation for abusing your position on the House Appropriations Committee...so you fire the people [1] who investigate that very thing.  Such appears to be the strategy of Rep. Jerry Lewis.  He claims it was a "bipartisan" decision...but it wasn't [2].

Rep. Lewis (R-CA), the powerful House Appropriations Chairman seems to be feelings the heat of the growing corruption investigation surrounding his ties to a lobbying firm run by ex-Rep. Bill Lowery and money he may have steered to clients of the firm who passed campaign cash his way.   His recent FEC filing shows he's out about $800K in legal fees, and Public Citizen's recently released report [2] shows Lewis to be the top House recipient [3] of lobbyist contributions. 

Definitely fire the investigators...that makes you look really innocent.