Karl-Heinz Borchardt is a lecturer at Germany's University of Greifswald. But 47 years ago, he was an 18-year-old being removed from his family's home in East Germany and hauled off to jail by the secret police. Borchardt's crime? Writing letters to his favorite radio program. The BBC looks at Letters Without Signatures, a program it ran for 25 years during the Cold War, and how the Stasi doggedly hunted down East Germans like Borchardt who dared write to it. "The letters are authentic and unfiltered," an expert on Letters Without Signatures says of the program. "The writers knew there was no censorship here and they spoke from their hearts." For Borchardt, being able to express his true thoughts was "like coming up for air."
Borchardt wrote his first letter as a 16-year-old in 1968, hiding it underneath his homework in his family's living room. He would write three more letters before the Stasi found him. The East German secret police took saliva samples and fingerprints from the letters they managed to intercept. But it was his handwriting that betrayed Borchardt. In 1970, his class was told to write an essay about their life goals. The essays were turned over to the Stasi and compared to handwriting from the illegal letters. Borchardt was taken from his home on the last day of summer vacation. He spent eight months in isolation in jail before being convicted of "attempted subversive activities" and sentenced to two years in a youth prison. Read the full story, including how Letters Without Signatures got its letters and why Borchardt never left East Germany, here. (Read more East Germany stories.)