At the end of April 1945, German soldiers opened a cupboard on the farm of the Dijkema family on Geefsweersterweg between Delfzijl and Meedhuizen. Instead of food or civilian clothes – in order to cross the border disguised as civilians – they find two Jewish people in hiding. The undoubtedly terrified men were Lazarus and Meijer Sleutelberg.

Until they went into hiding, the unmarried brothers worked in their father's butcher's shop at 38 Koestraat in Farmsum. While a large part of the Jewish population of Farmsum and Delfzijl was deported from March 1942, the Sleutelberg family was allowed to stay at home for the time being. Father Borach was partially paralyzed as a result of a stroke and the doctor from Delfzijl Dubbelinga and Reverend Van Vlier convinced the German authorities that he could not be transported in this condition.

The year of postponement of deportation had almost expired at the beginning of March 1943. Both brothers then decided to go into hiding, despite their father's precarious condition. Mother Sleutelberg stayed with her husband. That same month, the couple was arrested. Father Borach died two days after arrival in Camp Westerbork, mother Judikje was gassed immediately after arrival in Sobibor in early April.

Lazarus and Meijer found shelter at different addresses in the area. Eventually they ended up with the Dijkema family. There they seemed to be heading towards liberation in the second half of April 1945. Over the Geefsweersterweg, German soldiers withdrew ahead of the advancing Canadians towards the heavily defended port city of Delfzijl.

A group of German soldiers suddenly decided to search the farm. Meijer and Lazarus ran out of time to reach their hiding place in the barn. They therefore decided to hide in a closet – with the aforementioned fatal outcome. The soldiers took the brothers to the Sicherheitsdienst office in Delfzijl, also Jantje, the daughter of farmer Dijkema. She was released after a day, Meijer and Lazarus remained in prison.

In the night of 24 to 25 April 1945, the SD men August Neuhäuser and Siert Bruins transported the men in a car. Lazarus and Meijer then had to dig their own grave in an unknown place, after which they were shot. The SD men always remained silent about the final resting place of the Keyberg brothers, whose bodies have never been found. They were presumably shot in the area where the Farmsumerhaven is now located, near the Jewish cemetery.