An ill-conceived love letter was about to be handed to the secret police by a meddlesome manager, which would have devastating consequences for the people of the Protectorate of Bohemia and Moravia. It would give Karl Frank the excuse he needed to create a narrative, however bogus, to link the Bohemian village of Lidice with the assassination of Heydrich.

On the 3rd of June 1942, the large battery-making plant, the Palaba Factory, in the town of Slaný, 25 miles from Prague and just outside Kladno, received an envelope in the daily mail addressed to:

Pála Factory, Ltd., at Slaný

The lower-left corner of the envelope was marked with a clearly written note:

Andulka, factory number 210

The factory owner and Mayor of Slaný since 1940, Jaroslav Pála, opened the letter without authorisation and read a note from a man to a young employee, Anna Maruszáková.

Dear Anička,

Excuse me for writing so late and perhaps you will understand because you know I have much work and many worries. I did what I wanted to. On that fateful day, I slept somewhere at Čabárna. I am well. See you this week and then we shall not see one another anymore.

Milan

Publicly minded Pála sensed something was wrong. He called the local gendarme, who arrived in the shape of František Vybíral. Vybíral thought it was an ordinary love letter, but Pála, as a civic leader, took a more studious, cautious approach. He found the nature of the letter suspicious—potentially the handiwork of one of Heydrich’s attackers—and demanded further investigation. Vybíral was unable to warn Anna Maruszáková in time, and the Gestapo detained her the same afternoon.

Under interrogation, Anna spoke about an unidentified man with whom she had had an illicit affair. Little did she know that his real name was Václav Říha and he had been married for a short time. This suggestive letter was his way of trying to end the secretive relationship. He had allegedly asked her to remember him to the Horák family in Lidice, saying that he was well and not to worry. She was unable to tell them more about him, except that he had pedalled off to the small village of Čabárna in the Slaný District.

The Gestapo had already researched the background of the Horáks. They had found out, after checking with the gendarmes in the neighbouring town of Buštěhrad, that a Horák family lived in the village of Lidice. A son, Josef, together with a young man by the name of Stříbrný, also of Lidice, had emigrated to England. Of course, the Kladno Gestapo did know of that fact, and it was no major surprise to German authorities.

Nevertheless, an official of the Kladno Gestapo figured out that Anna Maruszáková did have contacts with Horák, who, he felt, might have been dropped in Bohemia as an assassin. Revelations concerning Marie Moravec’s son and his possible connections within the RAF to Horák and Stříbrný would also be fresh in the minds of key agents at the Gestapo.

But there were other reasons why Lidice could have been targeted by the Nazis in reprisal for Heydrich’s death: Kladno was a natural candidate for Nazi retribution. For the occupiers, the region was a constant irritant, causing discord, disruption, and interference. The City of Kladno had a reputation for being full of troublemakers and a hotbed of resistance.

Kladno grew up as an industrial powerhouse, providing the Austro-Hungarian Empire with iron and steel during the late 1800s but receiving little in terms of public health, housing, and hygiene in return. Resultantly, Kladno became the centre for Trade Union activism, communist support, and anti-Nazi sentiment in the 1930s. As far as the Nazis were concerned, it was about time revenge was meted out on the region.