Here is an interesting exerpt from an interview, from “No More Silence” by Larry Sneed, of David Harkness, DPD regarding seeing Jack Ruby on 11/23/63 in Dealey Plaza:
We didn’t know when Oswald was going to be moved, so I had a no parking area across the street, put up some barricades, and assigned some officers there to keep everybody back. Some newsmen were there including Wes Wise, who later became mayor, but we wouldn’t let anyone next to the area where they would back him in to the jail. I also noticed that Jack Ruby was down there at Elm and Houston, and I wouldn’t let him in the area either. But I did see him there that morning. I didn’t know him very well, but he had a nightclub downtown, and when I was working downtown I’d see him there at night. He had a couple of little dogs that he’d walk in the area around the hotels. But when I saw him in this restricted area, I just told him that we wouldn’t allow any pedestrians on this side of the sidewalk. I don’t recall whether he said anything, but he left.
I knew Wes Wise had seen him there, but didn’t realize that Harkness had to run him out of the restricted area near the jail entrance. At any rate, in my opinion, it is more evidence that Jack Ruby was likely stalking LHO.