"Mr. Moro is a known militant of a party that has many names in this corruption scandals"- Dude, what are you talking about?
"and is often clicked happily socializing with investigated politicians of such party"- With "ofen" you mean "one time situation in a public event on the stage where there were fixed places to sit?

You cannot be fair to him saing he should investigate the oposition, a judge cannot chose who to procecure, it happens to be the party in the office who stole the Petrobras, who else would be?