Steel doors and window frames are electrified through the use of household electric cords from which insulation has been stripped. "Pungi boards' are another devise consisting of plywood boards with nails protruding upward. These devices are placed on the floor inside the entrance. A trip wire may be placed in front of the pungi board. To avoid being injured by these devices, police investigators must be alert, observant, and cautious to find the booby trap before it finds them. They must also avoid tampering with these devices unless they are certain that they are using the correct procedures. Photographs