Another excellent article about the psychological profile of a kidnapper. This one with Brad Garrett, who served as then principle FBI behavioral profiler:
..."They tend to be white males, they tend to be a little older, in the 30-40 year age range, they tend to have a history of problems in relationships in general but in particular with women, they may or may not have a criminal history....
They tend to be somewhat — but not all of the time — socially isolated...
In general, they feel inadequate and one of the things in abducting, controlling and sexual assaulting is: it's about power. They are in charge, they are doing what they want to do, not what someone else wants them to do. They get what they want..."
Profiling abductors: Q&A with Brad Garrett | CBC News