Getting the authorities involved in a child custody case is not always a good idea. If you are a parent and someone has called the Illinois Department of Children and Family Services on you, you need to do some basic research and ask questions to determine what your rights are under the law.
You need to have an attorney, first off. Advising your attorney and informing him or her that the authorities at DCFS have been called in is important. Anything that you tell the investigator or the police in this case can be used against you, so don't answer any questions unless your lawyer is there with you advising you.