As the third-largest local police department in America, the LAPD cannot accept such an outcome, seeing as how its overall interests are at stake there.
From the standpoint of Gru's personal position, he is now essentially the top man at the LAPD; any disciplinary action against him would require a special investigative committee formed by California, with whom he has already aligned himself with the California heavyweight, Niu Sen.
The only man who could prosecute him outside of California would likely lead to a very frightening consequence.
If this matter were to be weighed, some ill-intentioned individuals could turn it into a responsibility of immense weight.
That man wouldn't have to carry this tremendous responsibility; on the contrary, it's another sword he's been dreaming of to use against the Democratic Party.
"If we report him, California won't deal with him, and the only outcome will be to hand that man a knife."