Please help!!?

I am a recently divorced mother of three. My ex-husband lives in Tennessee; I live in Kentucky. Recently “Sunday, April 6th, 2008”, My son came home with bruises after a visit with his biological father. He confided in me that his father grabbed him up by the throat and kicked him. This was collaborated by his younger sibling. His younger sibling told me over the phone that this had happened on the day that it happened. His father denied it. However my son, without coaxing, revealed the same in his monthly therapy. I was told to inform the proper authorities, which I did. However, since my ex-husband and I reside in two different states and the incident happened in my ex-husbands state of residence, no child protection organization will intercede on my child's behalf and step in. I keep getting put off in both states even though my son's pyschologist called them after seeing the bruise as well. I don't have a lot of money and am at a loss. Any advice? Thank you!!