Of course not, but if the cops are convinced no other person was connected to the crime and have found no other conspirators involved in the case, there would be little or no reason not to release the video. No?
That’s the point, they may say they are convinced, but that doesn’t mean they are.
Why put a suspect on notice you know about them? There’s investigative value to not letting them know, and depending on the situation, there could be value in making sure they know. It can go either way.
At this point we, the public, cannot make that call.