I'd be inclined to say Water Police because your example's eagle is "hollow". Officers' cap eagles are usually seen to be solid & much thicker. That said, this is still a nice example.
This one is also an enlisted eagle. The officer eagles are two piece or at least the eagle is very proud from the wreath. These gold eagles were also worn by traffic policemen (Vehehrspolizei) and there were a lot more of them than WSP or General Officers.