I hate it when the cops lie to protect their own. It really does seem to happen all the time. Sometimes, it's a matter of interpretation where an agency reads what appears to be a straightforward policy in a way different from how the public does. I can live with that, especially when a policy is vague.
But in this case, there was evidence on video all over the internet from multiple sources that the police were just plain lying about what happened, and they kept telling those lies in the face of it.