Vanceboro International Bridge Bombing - Arrest and Imprisonment

Arrest and Imprisonment

The sheriff for Vanceboro, along with two Canadian police officers from McAdam, New Brunswick who crossed the border to provide assistance, detained Horn at the hotel. Horn reportedly changed into his German army uniform (to avoid being arrested as a spy which was an executable offence) and surrendered to American authorities. Since the bomb exploded on the Canadian (St. Croix, New Brunswick) side of the bridge, the only charge that the United States could initially lay against Horn in order to detain him was a mischief charge for breaking windows in Vanceboro.

Horn was moved soon thereafter to a jail in Machias for his safety (Vanceboro residents were upset with him over the damage he had caused them) while Canadian authorities began the process of seeking his extradition. Horn was interrogated by the Federal Bureau of Investigation for several days and signed a confession with an agreed-upon statement of facts where he revealed the details of his crime.

Horn faced a federal grand jury in Boston, Massachusetts at the United States District Court for the District of Massachusetts and was indicted on March 2, 1915 for his most serious crime while in the United States - a charge of transporting explosives on a common carrier that also transported passengers for hire. He was sentenced to serve 18 months at the Atlanta Federal Penitentiary, Atlanta, Georgia.

After serving his sentence, Horn was extradited to Canada in October 1919 and was tried in the Court of Queen's Bench of New Brunswick in Fredericton, New Brunswick. He was found guilty and sentenced to serve 10 years at Dorchester Penitentiary, Dorchester, New Brunswick. Horn was assessed by Canadian prison authorities to be insane in July 1921 whereby he was released and deported to Germany.