On this day in 1916, U.S. federal authorities arrested two German agents in Trenton, New Jersey on suspicion of sabotage.

Under question the agents were discovered to have been plotting to bomb the Black Tom Island munitions factory near Jersey City; this discovery further soured already acrimonious U.S.-German diplomatic relations and pushed the United States and Germany one step closer to the brink of war. America would finally step over the brink four months later with the disclosure of the infamous Zimmerman telegram.