Judging from the shots I saw, that’s the exhaust plume of a solid propellant rocket motor. The point of origin is either at sea level or from a subsurface launch. The trajectory is definitely that of a missile. The flight profile looks like either a cruise missle or SAM and not a ballistic missile.
The question is what do the FAA radar tapes reveal origin, course, and speed?
Then, who’s the responsible party?
The fact that nobody is taking responsibility or seeming to not know what it was says it all. Zero information, (we’re checking into that folks...”) means lips shut tight from all sectors and that is fine with me.