Parental alienation (PA) is defined as an emotional disturbance in which a child sees one parent as good and the other as evil. PA is often seen in children whose parents are going through a divorce or custody battle. When the primary parent brainwashes the child, the case becomes known as parental alienation syndrome. The child begins showing extreme hostility toward the "evil" parent, verbally vilifying him or her and refusing to do anything with that parent. Proving PAS in court can be difficult, as children with the syndrome are known to be deceptive, and finding evidence is not easy.
Keep a diary of how your child acts when he is not around you. Try finding any witnesses who have frequent contact with the child and get them to record any denigrating things the child says about you in their presence. They could become assets in court. Children with PAS have been known to contort stories to make alienated parents look worse than they are. This behavior is promoted by the alienating parent, who tells the child false information about you. The child then repeats this information around other family members and friends. An example would be a mother who has primary custody repeatedly telling her child that his father is worthless and does not care about him.
Pay attention to how the alienating parent with custody lets you interact with your child. PAS parents have been known to directly interfere with custody and visitation rights, prevent the alienated parent from attending school functions and not allow the child to keep any gifts received from the alienated parent. Bring these issues up in court. Record them in your diary as well.
If you can, get the alienating parent to admit lying to your child about you. Record the conversation and any other incriminating evidence using a hidden tape recorder. Compile all of your evidence and contact an attorney. Attempt to reverse the alienation by spending as much time with your child as possible. Maintaining that relationship can help the child realize what he has been told about you is not as true as he believed it to be.
Get support from friends and family during this time. They might even be able to testify on your behalf in court.
Maintain a level-headed attitude at all times. Do not engage in any alienating behavior and slander the other parent, no matter how much he or she has slandered you.