Van Beek's active work against the Nazis began in the Red Orchestra resistance organization after she had gotten to know Libertas Schulze-Boysen in autumn 1941.
Together with her friend, the author Heinz Strelow, she distributed illegal writings and leaflets which sought to arouse readers to the struggle and resistance against the Nazi regime.

In the course of the suppression of the resistance group, van Beek was arrested by Gestapo agents on 20 September 1942 in her father's pottery shop in Berlin.
On 18 January 1943, she was found guilty at the Reichskriegsgericht military court of "abetting a conspiracy to commit high treason" and sentenced to death.
A clemency appeal of the 22-year-old was personally denied by Adolf Hitler, though the court itself had suggested a reprieve.
She was guillotined on 5 August 1943 at Plötzensee Prison in Berlin, together with 19-year-old Liane Berkowitz, who had given birth to a daughter in April.
Her body was released to the institute of anatomy of Hermann Stieve on the same evening.
Her final resting place is unknown.

Cato's younger sister Mietje Bontjes van Beek managed to escape Nazi persecution and lived in Fischerhude until her death in 2012.
Cato's mother, after a 12-year process, finally reached the official reversal of her daughter's conviction in 1999.
Van Beek's active work against the Nazis began in the Red Orchestra resistance organization after she had gotten to know Libertas Schulze-Boysen in autumn 1941. Together with her friend, the author Heinz Strelow, she distributed illegal writings and leaflets which sought to arouse readers to the struggle and resistance against the Nazi regime. 
In the course of the suppression of the resistance group, van Beek was arrested by Gestapo agents on 20 September 1942 in her father's pottery shop in Berlin. On 18 January 1943, she was found guilty at the Reichskriegsgericht military court of "abetting a conspiracy to commit high treason" and sentenced to death. A clemency appeal of the 22-year-old was personally denied by Adolf Hitler, though the court itself had suggested a reprieve. She was guillotined on 5 August 1943 at Plötzensee Prison in Berlin, together with 19-year-old Liane Berkowitz, who had given birth to a daughter in April. Her body was released to the institute of anatomy of Hermann Stieve on the same evening. Her final resting place is unknown.
Cato's younger sister Mietje Bontjes van Beek managed to escape Nazi persecution and lived in Fischerhude until her death in 2012. Cato's mother, after a 12-year process, finally reached the official reversal of her daughter's conviction in 1999.
Cato Bontjes van Beek