Fire hydrant accident on 4th of july penalties

My other half and I were driving to a busy 4th of july celebration in two vehicles. I dropped of grandpa and my daughter and wint to park. I could not find them and call him in a panic. He found parking in a empty lot where hundreds of other cars were parking. He jumped the curb like others but nicked a fire hydrant. No damage to the fire hydrant that he could see but either the curb jump or the hydrant nic popped his tire. He wint to park. Left his number on the window and came to find our daughter. We after about an hour and a half of both of us having no luck finding our daughter and grandpa we did get a hold of security and the local police. (Should be proof that we did have a real emergency?) The police sent a letter last week mid August asking us to call them. He did and did tell her the situation, the detective kept insinuating he needed to come in but not giving a reason. What is going on and what are the penalties?