When the sons of Icek Berkowicz asked Kostrzewa for shelter, their father, who Kostrzewa had known before the war, was already dead. Only Szmul and Moniek survived the war, while the rest of the Berkowicz family from Jeżów, near Skierniewice, died, having been transported to the ghetto in Rawa Mazowiecka.
The brothers Berkowicz spent two years in Kostrzewas’ house, hiding in turns, in the barn, cellar, and in the attic of the cowshed or of the house. Moniek obtained food at night, and sometimes he would leave during the day with Jan, Kostrzewa’s son. Once, the boys went swimming in the peat bog, and another time they went to gather honey.
Moniek was the first to come to the Kostrzewas, he brought his elder brother Szmul. They were later joined by their sister. Kostrzewa hid her in the potato cellar. Soon Moniek found a hideaway for her in a nearby village, but she was chased away.
“She was walking along a road when a man on a bike approached and grabbed her - says Jan Kostrzewa - because he was an anti Jewish person. She was also held by another man. They took her to the military police. They beat her on their way. She did not tell them where she had been hiding, where her brothers were. Not a word. They took her outside of town, by the narrow-gauge railroad, near the gravel mine. That is where they shot her.”
For a short time, the Berkowiczs joined the Jews who were hiding in a nearby forest. Jan’s father helped them organize a kitchen, but the locals found and destroyed the hiding place, and beat the fugitives from the ghetto. Moniek and Szmul returned to Kostrzewa’s. Another time, Moniek was caught by ‘Kulawiak’ a local roughneck. As he was taking him to the military police, the boy managed to break free. ‘Kulawiak’ tried to catch him, but was ordered by some peasants to let the boy go. After the war, ‘Kulawiak’ claimed he had only been joking.
In 1945, the Berkowicz brothers went to Łódź, and later left for Israel. Jan Kostrzewa visited Moniek in Tel Aviv.
