No, the officer wasn't proven innocent.  He was taken off the street, but he wasn't fired.  Incredibly lenient treatment for what he did.  They get a margin of error that you or I wouldn't get.

If either one of us saw someone backing out of the driveway in our car, if we grab a gun and shot them as they drove off, we'd go to prison.  That's a lot more illegal than the car theft.

It's incredibly inhumane that you think the way you do.  We're all flawed and we all make mistakes.  We don't get executed for it.  We're talking about a young human being here, not a statistic.