In late 1944, as the noose cinched around the Third Reich, the Nazis formed assassination squads to target collaborationists and the Allies alike.

Joseph Goebbels had spread his lies well. By the autumn of 1944 Germans of all stations and inclinations were convinced their country was about to be overrun by blood-lusting barbarians from both East and West. Goebbels was a masterful propaganda minister, able to convince many listeners his every word was fearful truth. The atrocities of the Soviet Union’s vengeful Red Army were already making headlines in Germany, and when U.S. Treasury Secretary Henry Morgenthau Jr. announced his punitive plan for administering postwar Germany, Goebbels made the most of this, too.

Morgenthau proposed dismantling German industry and refashioning the country based on agriculture. Observers realized his plan to create a “pastoral state” would be utterly insufficient to support Germany’s estimated postwar population of 65 million, and Goebbels hammered home that point. That Morgenthau was Jewish was a bonus bit of propaganda the “Poison Dwarf” made certain to deafeningly exploit. Thus as the Allies bore down on the German frontier, they encountered increasingly fanatical resistance.

On October 2 U.S. Lt. Gen. Courtney Hodges’ First Army besieged Aachen—the first German city directly attacked by Allied ground troops—and the Americans were shocked at the defenders’ ferocity. Not until October 21 did First Army units secure the urban wasteland that in the Middle Ages had been de facto capital of the Holy Roman empire.

Although little remained of Aachen, civilians began trickling back to the charred rubble of their city, determined to rebuild and start over. The occupying authorities had the same idea. They needed someone competent and trustworthy to oversee the daunting task of resurrecting the medieval metropolis and guiding it into the post-Nazi modern era. They hoped to find a local who understood Aachen and was also politically acceptable to the occupying forces. When American officers asked Catholic Bishop Johannes Joseph van der Velden who was the best man for the job, the cleric instantly responded, “Oppenhoff!”

A three-man reconnaissance patrol from the U.S. 1st Infantry Division moves through Thimister, Belgium, some 15 miles southwest of Aachen.

Franz Oppenhoff dearly loved his country but never had much use for the Nazis. He had been one of very few trial lawyers in prewar Germany willing to represent those indicted for anti-Nazi inclinations, and his zesty defense of such clients had branded him as one of them, garnering him a thick file at the local Gestapo headquarters. When war came, his unconcealed detestation of Nazism had put him at certain risk of passage aboard a cattle car to Dachau. But he had abandoned his law practice and cleverly taken a draft-exempt position as an executive with the Veltrup armament works in Aachen. By involving himself in a wartime industry and becoming proficient at it, he had hoped to make himself invulnerable to arrest, though his enemies kept trying.

The final attempt by party authorities to draft Oppenhoff (this time into a Luftwaffe anti-aircraft unit) came in early September 1944 when he was 42 years old. Determined to remain a civilian, he fled his beloved hometown just ahead of Hodges’ forces. He was living with his family in nearby Eupen, Belgium, when the Allies asked whether he would accept appointment as Bürgermeister (mayor) of Aachen and oversee its reconstruction. Ever the ambitious optimist, Oppenhoff agreed.

Days later newspapers covering the unfolding situation in Aachen reached the German legation in Madrid, which forwarded the news to Berlin. When Adolf Hitler and Reichsführer-SS Heinrich Himmler learned a collaborationist civil government was administering Aachen, the Führer flew into one of his customary rages. The treasonous puppet must be eliminated, Hitler screamed. Himmler would see to it.

As a typically frosty November broke over bleeding northern Europe, Himmler busily drew up plans for an organization he imagined would not only assassinate Oppenhoff but also bedevil the invading Allies. The Reichsführer selected General der Waffen-SS Hans-Adolf Prützmann to put together a team to kill Oppenhoff. Himmler dubbed the commandos “Werewolves,” a reference to the 1910 Hermann Löns novel Der Wehrwolf, in which Saxon peasants during the Thirty Years’ War form militias to repel marauding invaders.

Prützmann was a war criminal many times over. From June through November 1941 he had arranged the murders of tens of thousands of Latvian Jews. Knowing the Soviets had a hangman’s noose waiting for him, Prützmann realized he could only stave off death as long as Germany remained in the war. Such motivation made him the perfect man to marshal the Reich’s remaining resources in a desperate attempt to check the Allied juggernaut. Thanks to Goebbels’ propaganda-sown, nationwide xenophobia, Prützmann had little trouble finding volunteers for his first Werewolf operation.

In a whirlwind recruiting campaign he collected almost 5,000 young militants by year’s end and established a clandestine training complex in medieval Hülchrath Castle, some 45 miles northeast of Aachen. The surrounding village was not only isolated, but also conveniently near the Western Front, where the battered Allies were soon embroiled in the Battle of the Bulge and unlikely to launch any major offensives before spring. Just after Christmas, Prützmann and his officers code-named the Aachen mission Operation Carnival and began selecting a team.

Chosen to command the squad was 30-something SS-Untersturmführer (lieutenant) Herbert Wenzel, who, perhaps to make himself difficult to track in postwar Europe, gave each of his fellow operatives a different account of his background and wartime service. None was likely true, and Wenzel indeed soon proved adept at vanishing without a trace.

Second-in-command was massive SS-Unterscharführer (sergeant) Joseph Leitgeb from Innsbruck. The hulking blond Austrian was around 30 and reportedly not too bright. Still, he was surprisingly resourceful, blindly obedient and utterly fearless. A battle-tested veteran of the Russian front, he was a natural pick as an assassin.

Before the war 22-year-old Ilse Hirsch had lived in Aachen, and her familiarity with the city would make her a first-rate urban scout. As a woman, she was also less likely to be arrested by U.S. Army patrols more suspicious of military-age men wandering the streets. Like her teammates, Hirsch—a one-time member of the girls’ league of the Hitler Youth—was an unrepentant Nazi with few qualms about killing a turncoat countryman. She would be invaluable to the mission, as would the unit’s second, even younger scout. Sixteen-year-old Erich Morgenschweiss appeared as innocuous and disarming as a child. But after years of Hitler Youth brainwashing, he was as eager to pull a trigger as his older comrades.

The last two operatives were guides who would lead the killers from their drop zone into Aachen. Georg Heidorn had served in the area as an SS border patrolman and was familiar with every inch of the terrain. He was a dashing type with a jutting chin and deep-set, piercing eyes. Ostensibly willing as any to kill for his Führer, it would come to light he was nowhere near as courageous as he looked. Karl-Heinz Hennemann was the polar opposite of Heidorn. No one regarding his sagging jowls, perpetually agape mouth and overhanging forehead would dream that beneath his Neanderthal exterior hummed a mind full of energy, determination, nerve and cunning. He appeared a dullard but was actually a calculating, capable and ruthless soldier.

Every member of Operation Carnival realized from the outset the Allies would likely regard Oppenhoff’s assassination as murder and those who perpetrated it as war criminals. Were they captured and their objective discovered, they would likely receive the same treatment as English-speaking fellow commandos who had donned captured British and U.S. uniforms and parachuted behind Allied lines during the Battle of the Bulge: Those captured had been hastily court-martialed, tied to stakes and shot. Yet none of the Werewolves backed out or deserted.

Not until early March 1945 did the Werewolves complete their training, mission briefing, scouting and other assorted preparations.

Their plan was relatively straightforward: After parachuting into the Belgian countryside near the village of Gemmenich, they would move to their first base camp in dense woodlands along the German-Belgian frontier southwest of Aachen. Morgenschweiss and Hirsch would enter town and search for their target. After pinpointing Oppenhoff and memorizing his daily schedule, they would pass the information to Wenzel and Leitgeb. Following the assassination, the team would make their way east toward friendly lines. They were to stick to the plan even if separated. Traveling strictly at night, they would hide in foresters’ and game wardens’ cabins during daylight. All carried forged papers identifying them as members of the Reich’s Organisation Todt labor force. If captured, they were to try to convince their interrogators they were working on nearby border fortifications.

By March 20 the fighting had died down, and all was momentarily quiet on the Western Front. At 9 p.m. the half-dozen infiltrators heaved themselves aboard a captured, Luftwaffe-operated B-17 Flying Fortress at Hildesheim airfield south of Hanover in central Germany, and within minutes the bomber turned special operations aircraft was rumbling westward. Just before midnight the commandos leapt into the frigid night air over their designated drop zone. Once on the ground they quickly reassembled and collected their parachuted canister of supplies. But as they moved to their prearranged base camp, they stumbled across 20-year-old Dutch border guard Joseph Saive, who was strolling with his girlfriend when he spotted shadowy figures in the woods. As Saive swung his rifle off his shoulder and shouted a challenge, the infiltrators shot him dead. But the girl escaped and soon alerted authorities. The clock was ticking.

The assassins hurriedly split up and headed for Aachen via different routes. Hirsch arrived first and doffed her Luftwaffe coveralls to reveal the blouse and skirt she wore underneath. At dawn on the 21st she walked brazenly into the rubble-strewn city.

With a stolen basket draped over her arm, the young agent made a convincing show of being an unremarkable citizen out foraging. Finding Oppenhoff’s house was absurdly easy—she simply asked a passing old woman for directions. The condemned lived at 251 Eupener Strasse. Hirsch trekked to the neighborhood and spent the rest of the day casing it. She then had a fortuitous encounter with a young woman who had served with her in the League of German Girls. The friend gave Hirsch a place to stay.

Fortunately for the male members of the team, the Americans did not investigate Saive’s killing or bother to increase their patrols in and around the city. The men soon regrouped and resumed their march toward Aachen. Early on the morning of the 22nd they reached its outskirts and bivouacked in the forest. Wenzel decided to send Leitgeb and Morgenschweiss to reconnoiter the city, and the two soon happened across Hirsch.

Once the trio had rejoined their confederates, the team pitched camp in the woods near the Belgian hamlet of Hauset, about 90 minutes by foot from Oppenhoff’s residence. There they finalized their tactical plan. Hirsch, Morgenschweiss and Heidorn—the latter of whom had gotten cold feet—would guard the camp while Hennemann led Wenzel and Leitgeb into town to carry out the hit. At twilight on March 25, Palm Sunday, the gunmen, dressed in their Luftwaffe coveralls, set out for Aachen, about the time Franz and wife Irmgard Oppenhoff were putting their children to bed before strolling next door for a get-together with friends.

Just after 9 p.m. the assassins reached Oppenhoff’s house, Wenzel and Leitgeb entering through a basement window. Finding no one home except the children and the housekeeper, they woke the latter and explained they were downed German airmen who needed passes from Oppenhoff in order to return to their own lines. The girl ran to fetch the Bürgermeister. Wenzel and Leitgeb were waiting outside when Oppenhoff arrived with his neighbor. Sending the housekeeper back inside to make sandwiches, Oppenhoff spoke with the “airmen” while his suspicious neighbor excused himself and rushed off to alert the Americans. Left alone with their quarry, the assassins made their move.

Wenzel had assured his accomplices he would do the shooting. But when the moment of truth came, he lost his nerve. With a silencer-equipped Walther automatic in his shaking hand, he merely stood there, even when Leitgeb hissed, “Do it!” Snatching the pistol in disgust, the hulking Austrian barked, “Heil Hitler!” and put a bullet through Oppenhoff’s brain. After alerting Hennemann, who had been standing watch in a nearby vacant lot, the assassins vanished into the night.

As Goebbels had so dearly hoped, Oppenhoff’s murder made front-page news worldwide, and paranoia gripped the Allied high command as the toxic propaganda guru’s hysterical threats of unceasing covert warfare suddenly seemed legitimate. On April 1, a clandestine transmitter calling itself Radio Werewolf came on air. Signing on with a shrill wolf howl, it bragged about the assassination and announced the resurrection of the medieval Germanic Vehmgerichte, a secretive tribunal system Holy Roman emperors had employed to carry out vigilante death sentences. “Destroy the enemy or destroy yourself!” the broadcast urged repeatedly in coming weeks. An elated Prützmann ordered loyal Nazis on both sides of the front to liquidate every Bürgermeister in Allied-held territory. Oppenhoff’s death would prove an isolated incident, but for the moment it gave the Allied powers many sleepless nights.

Meanwhile, the Operation Carnival assassins were simply trying to get home.

After shooting Oppenhoff, Leitgeb became separated from Wenzel and Hennemann. Only he made it back to their base camp. Gathering up Hirsch, Morgenschweiss and Heidorn, he led them eastward into ever-deeper peril. On the morning of the 27th, as the team crossed a meadow outside Rollesbroich, Leitgeb himself triggered a land mine and blew his face in half. The following afternoon Hirsch walked into a tripwire, setting off an explosion that crippled her right leg, tore open Morgenschweiss’ back and injured Heidorn’s right arm. Concealing Hirsch in some bushes, the men left her to her fate. The next morning a farmer rescued the she-wolf.

That same morning, as Heidorn and Morgenschweiss continued eastward, the exhausted boy collapsed and refused to go any farther, which was fine with the self-interested Heidorn. After the war the teen claimed a local woman he knew only as “Frau Sülz” found him and coaxed him to an infirmary in the village of Vussem.

Half dead from blood loss, Heidorn struggled on alone, bound for an isolated farmhouse outside the nearby town of Mechernich. Though it was a designated safe house, he was stupefied to find Wenzel and Hennemann waiting inside. After resting briefly, the trio again set off east. When they reached the Rhine, Wenzel bid the other two farewell and split off without any further explanation. Heading to another farm set aside as a refuge, he worked hard and kept quiet until August, when he caught a ferry across the river, struck out eastward and disappeared from history.

Heidorn and Hennemann managed to swim the Rhine, only to be arrested by a U.S. patrol. Assuming their prisoners were run-of-the-mill POWs, the Americans sent the pair to a nearby internment camp—in Aachen. Released soon after, they returned to their homes in what became East Germany.

At war’s end Prützmann surrendered to the British. But before they could identify him as one of the most wanted war criminals in Europe, he committed suicide by biting into a cyanide capsule.

It was 1949 before the Allies could unearth and examine enough captured documents in chaotic postwar Germany to identify Oppenhoff’s killers. Wenzel eluded capture, but that fall Heidorn, Hennemann and Hirsch were brought to trial in Aachen. Morgenschweiss turned state’s evidence, appearing as a prosecution witness.

Most assumed the accused would be speedily convicted and executed for the murder, as they had freely admitted their guilt and were brazenly unrepentant. However, Hennemann’s attorney won a reprieve for all three defendants by producing a surprise witness named Lennertz. A former partner in Oppenhoff’s law practice, Lennertz claimed to have seen Oppenhoff in a German army uniform in September 1944, just before he fled to Belgium. According to Nazi German law, this made the deceased a military deserter, without the right of trial before execution. The prosecution was able to convince the tribunal to find the assassins guilty, but their sentences were token. Hennemann got 18 months, Heidorn one year. Hirsch was acquitted and released. Morgenschweiss was never even indicted.

Even if Lennertz had told the truth, and Oppenhoff had been an army deserter, the sentences were absurdly cheap for the life of a noble man who sought nothing more than to rebuild his beloved country after the Nazi nightmare. In his absence and despite the broadcast threats, many others stepped forward to heal the destruction and desecration wrought by the malevolence of the Third Reich.

Their murder of Oppenhoff was the only time the Werewolves howled loudly enough to be heard outside Germany’s borders. As it had for their one noteworthy victim, death ultimately came calling for them. 

Kelly Bell is a military history writer whose work has appeared in World War II, Vietnam, Aviation History and other magazines. For further reading he recommends The Last 100 Days, by John Toland, and Werewolf and The Battle of Hürtgen Forest, both by Charles Whiting. This articles was published in the July 2017 issue of Military History Magazine. For more stories, subscribe here