The use of a grand jury isn't indicative of a 'cover up'. There's been zero indications of a cover up. For crying out loud, they charged her. If they'd exonerated her, perhaps you could make an argument. In fact, this case has been text book of what you're *supposed* to do when an officer shoots someone, especially when there is a racial component.
The charges have been reasonable and timely. The investigation was given to an outside law enforcement office. And the Dallas PD is keeping the public informed.
And the officer isn't 'anyone else'. If she was, we wouldn't be talking about her. They also wouldn't have given the case to the Texas Rangers. The involvement of the officer and the calling in an independent investigative team added about 48 hours to the case.
There is so far, zero indication of a cover up.