Year Event Location Perpetrator(s) Deaths Injuries Comments 1864 Confederate sabotage of Gen. Ulysses S. Grant’s headquarters City Point, Virginia John Maxwell of the Confederate Secret Service 43 to 300 125 Maxwell called his device a "clockwork torpedo"; placed on an ammunition barge, it detonated 30,000 artillery shells[1] 1875 Attack on the Mosel (ship) Bremerhaven Alexander Keith, Jr.