In this case, the prosecutor declined to charge. There was an investigation on suspicion, and nothing more. Lewandowski was never charged, although from reading the news reports, I'll wager 90% of the public believes he was.
“Police later charged Lewandowski with simple battery, releasing video from surveillance cameras that shows Lewandowski reaching for and grabbing Fields.”
The police charge the prosecutor decides not to prosecute the charge. That’s the way I read it. It makes sense.