Such a person can do no wrong
used for saying that someone is considered by other people to be perfect, although you may not agree with this opinion
His parents think he can do no wrong.
He might also be called above the law
in a position where one can avoid being bound by the laws that govern ordinary people.
"the army was above the law and enjoyed complete impunity"
Or untouchable
not able or allowed to be touched or affected.
"drug barons who were legally untouchable"
The cause of these latter two could be that everyone believes him innocent; however it could also because people believe him too powerful and dangerous to be stopped.
And, to some extent (i.e. literally), the person is a hypocrite
a person who pretends to have virtues, moral or religious beliefs, principles, etc., that he or she does not actually possess, especially a person whose actions belie stated beliefs.