The Regulation Police is an I frame gun, and parts will be hard to come by. You might try www.gunpartscorp.com or write them as sometimes they have a few parts not worth cataloging. There also may be a few J frame parts that will work or can be made to work. In the picture, it looks like the topstrap might have been broken and welded/brazed back together. If that is the case, the gun is a paperweight even at the low power of the .32 S&W and .38 S&W
Jim K. Thank you for the link, I will check with them. The gun has not been broken or re-welded. The original nickel finish is in really bad shape. The tension screw is missing as well as a screw for the side plate. I also need a thumb piece and thumb screw. It looks like the previous owner used the gun as a hammer as the grips are knocked like it was used to strike something.