OK, here's the "Caddy," Photoshopped. I have used the liquefy brush to take the "fisheye" distortion away from the rear half of the vehicle. I also changed the lighting a bit to make it easier to see the body work at right rear. This is a much more accurate picture of the car we're looking for. I would recommend that anyone looking, use THIS fixed version, instead of the original surveillance capture.
Now, after fixing it, I have carefully examined it again, to see if it may be a Cadillac Eldorado (a 2-door car). What makes me reject the Eldo is the long ridge that starts over the front wheel well. The Eldo ridge starts much lower.
I reaffirm my opinion that that's a 1979-'86 Fleetwood Brougham or an '87-'89 Brougham, or, (very unlikely) an Oldsmobile Delta 98.
Please click HERE to see my Photoshop repair of the distortion that has made the car look curved in the original shot.