Found this definition of kidnapping in a legal dictionary.
kidnapping n. the taking of a person against his/her will (or from the control of a parent or guardian) from one place to another under circumstances in which the person so taken does not have freedom of movement, will, or decision through violence, force, threat or intimidation. Although it is not necessary that the purpose be criminal (since all kidnapping is a criminal felony) the capture usually involves some related criminal act such as holding the person for ransom, sexual and/or sadistic abuse, or rape. It includes taking due to irresistible impulse and a parent taking and hiding a child in violation of court order.
http://legal-dictionary.thefreedictionary.com/kidnapping