The district attorney letting Scorpio go

I understand this was needed for the movie, but the way they wrote it drives me crazy. Harry is literally standing there with two cracked ribs and a few facial lacerations/bruises, and the district attorney says there is nothing they can prosecute him with. Assaulting a police officer is apparently okay in 1971. The end of the movie should've been Harry kicking the crap out of that guy.