I think it is good to have competition amongst anti-corruption squads or law enforcers. Think this way: a corruptor can bribe the police, but, in competition, the general attorney office or KPK will still be more than willing to arrest him/her - and vice versa.
Now you may want to say: what if the corruptor bribe them all? It's possible, but at least it is now more expensive to do so than with single anti-corruption office. The competition raises the corruptor's cost of wrongdoing and make anti-corruption more efficient.
Better yet if we can somehow set an competitive auction mechanism in which police, general attorney office, and KPK can bid to arrest a corruptor and force this corruptor repay the certain amount of the state's loss, and the office proposing lowest operational budget would win.
Who's afraid of such competition (a.k.a the loser)? First, the one from less efficient office. Second, and the foremost, the operation target, that is the corruptor him/herself. The non-corruptor would have no objection about this.
Now, if you know someone fiercely takes troubles and makes a lot of fuss on this competition among anti-corruption agencies, you may ask yourself and be suspicious if he/she is either from the less efficient agency or Mr/Ms Corruptor him/herself.
We economist call it his/her revealed preference -- regardless her/his stated preference as self-proclaimed anti-corruption bravados.