CPA (DHS) unfairly holding back information.

I have guardianship of two grandchildren ages 5 & 6. Previously the parent had graduated to one unsupervised visit on Sundays. Due to two witness, one of them a friend of mine, and the other a social worker who knew the parent, the parent was out shopping at a store with no kids with him. I was sent a text on my phone and I immediately notified DHS. The social worker notified them as well. This was considered negligent... and opened up an investigation by the department, all the information proved to be founded. I was not mailed the Notice of Child Abuse Assessment report and I feel I should have a copy of it. When I emailed the case manager stating this, she said that I don't get to have a copy. Only the parent gets a copy. Ok, according to the law, a mandatory reporter may request a copy, and as a caregiver, aren't I a mandatory reporter? Also, I cannot find anywhere in the internet who the main CPS supervisor is. How do I find that information. ( I am in Webster County Iowa)