Abstract: A surveillance apparatus against theft or intrusion includes a box containing a detector reacting to an abnormal presence and operable to selectively activate a camera, a flash and/or an acoustic warning device. The open rear of the box is hingedly attached to a support plate affixed to a wall while flexible wires from the box components include a connector part removably attachable to a mating connector part on the support plate, the latter being supplied with a source of power. A backup source of power may be included in the box as well as cooperating lock components on the box and support plate.