In most states there are laws against indecent exposure as well as assault/battery. What you have described happening to your son is a criminal action as to the three charges set forth above. In essence there are various laws prohibiting the urination upon a person done out of spite.If your son is being bullied at school, you need to meet with the principal about the situation as well as the most recent act of urination upon your son's shoes.Rather than notify law enforcement about what happened to your son, I would be making a complaint with school officials as to resolving the problem.