Anti-theft apparatus

An anti-theft apparatus for a box-shaped article intended to be sold, such as a cassette with a data carrier, having a casing for receipt of the article, which casing includes at least one narrow side having a slide-in opening and a single transmitter adapted to trigger an alarm, having locking means arranged on and cooperating with said casing which are adapted to engage the article located in the casing, which locking means are adapted to be unlocked in order to separate the article from the casing, comprising a bracket-shaped auxiliary member guided at the inner side of one of two opposite narrow sides of the casing for a longitudinal displacement, which auxiliary member includes at both its ends a perpendicularly projecting stiff leg, whereby the box-shaped article is caught between said legs during a displacing, which bracket-shaped member has an end piece positioned at the outside which is elastically bendable to allow removal of the article from the bracket and insertion of said article when the bracket is in its drawn-out position, whereby the end of the bracket positioned at the inside includes a locking lug located adjacent the projecting leg and, as seen in a longitudinal direction of the bracket, positioned outside of the leg and projecting also towards the inside, which lug is adapted to snap into a locking slot at the narrow side of the casing located opposite of the slide-in opening when the bracket is at least substantially completely slid into the casing, whereby the desired unlocking is achieved by means of a special tool.