Mayor Tom McMahon spotted the graffiti on the park's police memorial statue while participating in the city's Memorial Day parade.
McMahon said he doesn't know "if this was planned because of the holiday or if it was just a coincidence," but he said, "it's unfortunate that someone chose to desecrate the monuments like this."
Police said the vandals also sprayed blue and white paint on a Christopher Columbus monument, a World War II memorial plaque and statues of Reading industrialist Frederick Lauer and President William McKinley.
McMahon said the city Public Works Department should be able to remove the paint.