An abductor is the person who takes someone away by force. News and police English like this word; ordinary talk more often says kidnapper. The ending -or marks the doer, as in actor. Put it next to abductee and the picture is clear: abductor takes; abductee is taken. Students mix those two, and it is an easy mix to make. Though actually, a doctor may also call a muscle an abductor, because it pulls a body part away from the centre. If your text is about crime, abductor means the offender. If your text is about the body, it may mean a muscle. Let the words around it tell you.