Abstract: A theft deterrent device, intended to be attached to a theft-attractive article so that it can be removed from the article with the aid of a deterrent release device in the possession of an authorized person, and such that any other form of removal will result in damage to the article concerned, includes a first element (10) having a connecting pin (12) which is intended to be inserted through the article to be protected, and a second element (13) which is intended for attachment to the connecting pin. The first element 10 includes a fragile ampule (17) which contains a staining liquid and which becomes fractured upon manipulation of the connecting pin 12. The ampule is positioned in such a way so that by applying a pulling force on the connecting pin in a direction away from the first element (10), the ampule will flex and break.