My ex husband has custody of my son and I have visitation rights he has disappeared. How do I find my son?

Your husband is in contempt of court and obstructing court ordered visitation and is a misdemeanor criminal offense but rises to a felony if the offending parent takes the child out of the state. I would file a contempt motion in the court and if you cannot serve him because you do not know his whereabouts you can serve him by a Warning Order filed in the Court, once that is accomplished you can get a hearing and the court can issue a warrant that will go out to law enforcement. Since your son has special needs I would imagine your ex-husband gets SSI on his behalf, you might be able to trace him through Social Security or through Arkansas DHS as his case might have been transferred to another state.