Home Maine The Vanceboro Bridge Bombing: Germany’s Secret War on America

The Vanceboro Bridge Bombing: Germany’s Secret War on America

How (and why) a hapless German spy tried to blow up a bridge in a remote corner of Maine

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On a wretchedly cold Maine night in 1915, a lightly dressed German army lieutenant walked from his hotel and placed 60 pounds of dynamite on the Vanceboro Bridge. The bridge spanned the St. Croix River, which separates Maine from Canada. With frostbitten hands, the German lit a cigar and touched it to the fuse. Then he ran back to his hotel, desperate to get warm.

Werner Horn, undated

The attack on the Vanceboro Bridge was a comedy of errors involving a hapless spy, a German diplomat, a sleepy deputy sheriff and a small Maine town where little went unnoticed. But it turned into an international incident when four governments, three of them at war, argued over what to do with Lt. Werner Horn.

The attack on the Vanceboro Bridge belonged to a larger German campaign of sabotage against the United States.  Before the U.S. entered World War I, it supplied the allied powers with munitions, foodstuffs and military supplies.  Despite official neutrality, the United States allowed Canadian Pacific trains to carry Canadian soldiers across its soil.

So Germany tried to interrupt the supply of munitions to Allies with a spy network inside the United States. Over a year after Werner Horn attacked the Vanceboro Bridge, German spies blew up 2 million pounds of arms and ammunition on Black Tom Island in New York Harbor. The explosion killed four and injured more than 100.

A shattered pier on Black Tom Island

Werner Horn didn’t hurt anyone.

German Sabotage

Horn served in the German army for 10 years until inactivated. He then went to Guatemala to manage a Guatemalan coffee plantation. There he learned Spanish and English.

Werner Horn around 1910

In August 1914, shortly after World War I broke out, Horn received a telegram saying he’d been reactivated. It also said he had to return to Germany.

Horn could travel freely to New York, as the United States hadn’t entered the war. There he found himself stranded, unable to book passage home. So he went to the German consulate for help.

Franz von Papen

Capt. Franz von Papen, then a German diplomat, had also received a telegram. It read:

The General Staff is anxious that vigorous measures should be taken to destroy the Canadian Pacific in several places for the purpose of causing a lengthy disruption of traffic.

The Vanceboro Bridge

With the arrival of Werner Horn, von Papen had a willing operative. He also had a target: the Vanceboro Bridge.

The Canadian Pacific moved troops and materiel through Maine and across the Vanceboro Bridge to the Port of St. John, a major shipping entrepot for Allied men and materiel during World War I.

Port of St. John around 1898

The Germans complained, correctly, that by doing so the U.S. violated international neutrality law.

But neither the U.S.  nor Canada seemed to understand that the iron railway trestle in remote Washington County was a key link in the wartime supply chain. They had left it unguarded since October.

Von Papen persuaded Werner Horn to blow it up. But he did it on one condition: No one would be hurt.

Maine Bound

Von Papen sent Horn to the tiny Maine town of Vanceboro with a train schedule, a .38 revolver, money, small German flags and a suitcase full of explosives. When Horn arrived at Grand Central station on March 31, he bought a first-class train ticket on the New York-New Haven.

For his mission the Germans dressed him in workingman’s clothes: torn pants, work boots, a brown overcoat and a woolen cap. That didn’t make him inconspicuous. He was tall, at six feet two inches, with short blond hair, a military bearing and a heavy German accent.

When he boarded the 1 am train to Boston, passengers took note of his shabby clothes, out of place in a first-class car.

In Boston, he switched to a train bound for Bangor and, ultimately, Vanceboro.

Nosy Neighbors

At 6:40 pm he arrived in Vanceboro. Perhaps not realizing how little goes unnoticed in such a small place, he hid his suitcase in a woodpile. Jean and Charles Hunter saw him do it. They then watched him traipse over to the bridge. The Hunters also noticed he wasn’t dressed warmly enough for the subfreezing temperatures. Charles went to see the local immigration officer, Inspector Carr Horn.

The Vanceboro Bridge before Werner Horn got to it.

Inspector Horn and Charles Hunter then returned to the bridge, where they saw Werner Horn walking back and forth, inspecting it. They confronted him, and Horn explained he was a Dutch farmer looking to buy land. The inspector suggested he check into the local hotel, the Exchange. Then several townspeople watched him retrieve his heavy suitcase from the woodpile.

Horn checked in to a first-floor room at the hotel. He spent the next day in his room, studying the railroad timetable. Unfortunately for him, it wasn’t very reliable.

Horn knew he’d have to walk a fine line. If he got caught blowing up the Vanceboro Bridge on the American side, he’d face criminal charges. If he got caught blowing it up on the Canadian side while disguised as a Dutch farmer, he could be hanged for espionage. So as darkness fell, he pinned his German flags to each arm of his overcoat and headed toward the Canadian side of the bridge. Von Papen had told him the flag would prove he wasn’t a spy.

But first he checked out of the hotel, telling the proprietor, Aubrey Tague, he planned to take the 8 pm train to Boston. He then walked to the train station in the snow, underdressed for the gusty wind and subfreezing temperatures. When the Boston train left the station he hid in the woods, planning to wait until the 11:30 from Montreal to St. John passed.

Blowing up the Vanceboro Bridge

Having studied the timetable, Horn expected he’d have an hour until the next train came through. He’d use a 50-minute fuse, which would give him enough time to blow up the bridge without hurting anyone. That would also allow him to make his escape. He planned to walk to the next town, 30 miles through the Maine woods, and get on a morning train.

Horn probably would have frozen to death walking 30 miles through the Maine woods

As he cased the bridge, two railyard workers spotted him and asked what he was doing there. He replied he was “an officer.” They believed him, figuring he was guarding the bridge, and left him alone.

When the Montreal-St. John passed he stepped onto the bridge with his suitcase, but he hadn’t gotten far when he heard another train whistle. He rushed off the bridge and waited for it to pass. Unnerved by the railyard workers and suffering from the cold, he now had no idea when the next train would come rumbling over the Vanceboro Bridge.

Horn picked his way across the bridge and heard another train coming. He flattened himself on Canadian ground, and he decided he had to act quickly.

He placed his explosive next to an iron post and, with his frostbitten hands, cut the 50-minute fuse down to three minutes. Then he lit the fuse and rushed back to the American side.

The Vanceboro Bridge Explosion

The explosion woke the residents of Vanceboro and St. Croix and broke windows on both sides of the river.

The blast woke Aubrey Tague, who then heard water running from a bathroom. He opened the door and found Horn shivering over a sink, running hot water over his frozen hands. Tague told him to put snow on them, opened the bathroom window and handed him a handful. Then he told him he could sleep in an attic room.

The sound of the bomb also woke Deputy Sheriff George Ross, who thought a boiler had exploded or a train had crashed, neither of which concerned him. He went back to sleep.

The explosion did little damage and delayed trains only slightly. Trains could still make it over the bridge.

X marks the spot where Horn placed his bomb. Canada decided to guard the bridge after the attempt.


At 5:30 the next morning, three railroad police knocked on Deputy Sheriff Ross’s door. Tague had spoken to railyard workers the night before about the stranger. The four police went over to the hotel and found Tague. “German, upstairs,” Tague said to them.

They found Horn in his room and took him into custody.  He answered their questions honestly. Horn later explained to a U.S. intelligence agent,

I really did it for my country. I did not want to kill anyone. We wanted only to stop traffic of British supplies over that bridge. I would have done a better job but for the cold. I froze my fingers and my face and ears and I thought I would freeze to death before I made all my arrangements.

He pointed out he had planted the dynamite in enemy territory, since Canada was at war with Germany. That meant he’d committed an act of war. And the U.S. couldn’t have him extradited to Canada or Britain because it had declared neutrality.

10 Years

Ross was at a loss. Feelings ran high against Horn on both sides of the river, and he feared a mob might gather and lynch the German. But he didn’t know what to do. The crime had happened in Canada, where he had no jurisdiction.

Nor had state or federal or authorities contacted him, just railroad police.

Finally, federal authorities got in touch with the Washington County sheriff, Ross’s boss. They told him to take Horn into custody for safekeeping in Machias. The sheriff said he didn’t have any grounds for arresting him. The feds told him to charge him with malicious destruction – those windows broken in Vanceboro.

A county court sentenced him to 30 days in jail. But Horn had also transported explosives by rail, which made him vulnerable to federal charges.

Dorchester Penitentiary

On March 2, 1915, he was charged with three counts of “the conveyance of explosives on passenger trains.” He was sentenced to 18 months in prison and sent to the U.S. Federal Penitentiary in Atlanta.

von Papen later admitted it hadn’t been his shining hour. “Not a particularly intelligent piece of work on my part,” he wrote.

Horn expected to go home after his release from prison. Instead, he was extradited to Canada, where he spent 10 years in Dorchester prison. Upon his final release, doctors certified him as insane.

Vanceboro Bridge

The Vanceboro Bridge has since been replaced.

Images Vanceboro Bridge today: By THE CENTER FOR LAND USE INTERPRETATION – http://www.clui.org/section/united-divide-a-linear-portrait-usacanada-border, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=47474541. Washington County Jail By Magicpiano – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=28029643. Dorchester Penitentiary By Verne Equinox at the English-language Wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=4230825. Werner Horn 1910 Bain News Service, P. (ca. 1910) Werner Horn. , ca. 1910. [Between and Ca. 1915] [Photograph] Retrieved from the Library of Congress, https://www.loc.gov/item/2014697286/. Horn and Ross By McAdam Senior Citizens Historical and Recreational Club (1979). The History of McAdam 1871-1977, p 180., Fair use, https://en.wikipedia.org/w/index.php?curid=20059952.

With thanks to German Sabotage at Vanceboro 1915 by the St. Croix Historical Society and Burn, Bomb, Destroy: The German Sabotage Campaign in North America, 1914–1917 by Michael Digby. This story was updated in 2023.



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