Not really. There are no "no-go" zones in the United States under most circumstances. Unless there is a clear and present danger, freedom of travel is a guaranteed right. Mere suspicion is not enough.
I guess the issue there is "most circumstances".
Say for instance a cop saw an angry mob approaching a public building, etc. His inclination would probably be to try to stop them before something bad happened. Granted, that would be "mere suspicion", but at times judgement is required.
Now, was this one of those times? I don't know. I wasn't there. Evidently it was in this cop's mind though.