He was accused of 'assault'. = He was charged with 'assault'. = 'Assault' charges were brought against him.
He came 'under assault' for his unusual beliefs. [=he was severely criticized for his unusual beliefs]
He was found guilty of 'sexual assault'. [=the crime of touching someone in an unwanted sexual way]
(..) stand up to him like that. What's going on? Hal, what happened? I think a bee flew up my nose. I was just about to make my frontal assault to rescue you, when like fifty ninjas tried to attack me. So I had to beat them all up, and I did... - and they were all like crying, so. - Wow. (..)2010 Megamind