The bomb was an improvised explosive device constructed in a small two-wheeled shopping cart with 2 baskets, one on top of the other. The top basket contained a gallon milk jug of gasoline, wired with a blasting cap. Below the jug in the bottom basket were 2 tuna fish cans filled with a mixture of aluminum powder and flour meant to aerosolize and deflagrate following detonation, each with its own blasting cap. Throughout both baskets were chain links, gunpowder, and boxes of ammunition acting as shrapnel. The mechanism was triggered by a dead man's switch, consisting of a wooden piece separating two metal connectors within the jaws of a clothespin, forming an incomplete circuit. The circuit was powered by a 9-volt lantern battery. Once the wooden piece was removed, the 2 metal connectors completed the circuit, detonating the bomb. The wooden piece was tied to Doris' wrist by a string.