WHAT SHOULD I TELL MY DAUGHTER!?

[antonin]

             
For many years, my son, (28) from another marriage would regularly visit my daughter at Christmas and the summer. He did this from the time daughter was born. The last time he visited was in July of 2002. In approximately early January of 2003, my ex-wife informed me that a counselor from a women's shelter had made a call to CPS concerning an alleged incident between my son and daughter.
I have tried to recreate the event that started this situation and have received bits and pieces from my daughter. EX enrolled herself and daughter immediately in the same women's shelter referred to above after EX filed for divorce in Sept. 2001.  
The FOC evaluator recommended 50/50 custody and I have been doing that since Oct 03.
Daughter did not attend individual therapy at the shelter on a regular basis, but was part of a group. This went on for 2 years. Apparently there was an exercise (Jan 2003) wherein the children were first asked to draw pictures of anyone who hurt them, identify that person, and then put some kind of sticker on that person. The way the exercise was conducted that every child was required to name someone that hurt them and the next child was not called upon until the previous child had named someone. My daughter named my son. Later, in talking with my daughter about the incident, she stated that my son did not hurt her and they were just playing and does not seem at all disturbed by the incident.
I never saw the report. My ex claimed that daughter stated that son had "tied her up." The women's shelter called CPS. CPS called the cops. The cops came to my house in Feb. 2003. They did not investigate because my son did not live in Michigan, but in Arizona.
My son was advised by an attorney not to talk to daughter or myself back in Jan 2003. My son is a junior high school teacher in AZ. My daughter is 9 years old now.
Well, it's August 2004 now and my son and daughter have been talking on the phone regularly.  

I HAVE RECEIVED ADVICE  FROM SOC AND LAWMOE THAT I SHOULD NOT HAVE MY SON AND DAUGHTER TALK ON THE PHONE. AFTER 2 YEARS, THEY ARE FINALLY COMMUNICATING AGAIN. I TRUST THE ADVICE AND MUST NOT HAVE SON AND DAUGHTER COMMUNICATE.

WHAT SHOULD I TELL MY DAUGHTER?!