It was about 5:30 p.m. on January 19, 1965 when two employees of a company situated directly on the Spree River in the West Berlin district of Kreuzberg heard cries for help. They followed the direction of the calls and saw a man, approximately 30 years old, swimming in the ice cold river toward the embankment.
Christian Buttkus started building his own diving equipment in August 1964. The couple’s original plan was to leave East Germany in the summer of 1965 by way of the Teltow Canal in Kleinmachnow. The chemical expert built an underwater vehicle to enable them to get through the water escape route as quickly as possible.
An unidentified man entered the Spree from the west bank between the Kreuzberg and Friedrichshain districts and swam towards the east side at around 9:30 p.m. on March 25, 1965. Twenty meters in front of the East Berlin riverbank near the Osthafen paper mill, the man, "presumably under the influence of alcohol" – as it was noted in a border troop report – asked the border guard for help.
Two short shots. Then he let go. Peter Hauptmann swayed backwards and collapsed, fatally wounded. The guard fired the signal "Help. Urgent" and ordered the second man, who until then had been in charge of guarding the sailors, to administer first aid.
The couple on the boat was observed by the two border soldiers stationed on the watchtower at the southern bank of the canal. The guards evidently felt provoked by Hermann Döbler and Elke Märtens, possibly because they had waved to them.
The twenty-five-year-old was found dead in an S-Bahn tunnel north of the closed down Bornholmer Strasse station on August 8, 1965 at around 11:30 p.m. S-Bahn trains traveling regularly between the Schönhauser Allee and Pankow stations passed through this tunnel, which was situated within the border grounds.
At around 9 p.m. a border guard watched as the 24-year-old climbed over a wire mesh fence on a lot on Paul-Gerhard-Strasse in Teltow-Seehof that was located very close to the border. The border strip was only 20 meters wide there.
By 2:45 a.m. the two young men had reached the garden property at "An der Stammbahn 53" in Kleinmachnow and proceeded towards the one-and-a-half-meter-high interior fence that closed off the property from the border grounds.
The young man caught the attention of the East German secret police in October 1959 when an informant reported that he had gotten into a drunken fight with the LPG chairman and said: "You communist pigs, the day will come when you will hang from trees!"
He approached the inner-city border grounds from Clara-Zetkin-Strasse, today’s Dorotheenstrasse, on November 25, 1965 at around 5 o’clock in the morning. Although it was still dark outside a border guard posted on a watchtower on the corner of Clara-Zetkin-Strasse and Ebertstrasse noticed him.
It was already dark when Erich Kühn tried to flee on the evening of November 26 from Kiefholzstrasse in the East Berlin district of Treptow to West Berlin. A large area had been blocked off around the grounds of the deserted tracks that ran across Kiefholzstrasse between the Treptower Park and Sonnenallee stations.
They reached the border crossing at Heinrich-Heine-Strasse at half past midnight on December 26 and lined up in the exit lane. When the brothers reached the front of the line they were asked to get out of their vehicle. A border soldier discovered Monika P. behind the backseat and called out: "Apprehend her!"