Since 1940, Stanisława Butkiewicz worked for Jakub and Chana Fajnsztajn (Fainsztein) as a babysitter for their one-year-old daughter Masza. The family lived on Zawalna Street in Vilnus. Jakub was a lawyer and Chana was most probably unemployed. In 1940, Jakub died of leukaemia.
Once Germans took control over the town, the Jewish population started to be persecuted and terrorised. On 6 September 1941, a ghetto was established in Vilnus. Chana and Masza Fajnsztajn were among those sent to live there. Chana worked in an office outside the ghetto and on her way to work, she always met Stanisława. After the war, Masza said: “When Jews were led to work outside the ghetto, my mother would always leave me in Stanisława Butkiewicz's house on Szkaplerska Street. One day, in October 1941, she said: «Stasiu! Take care of her, because I don't know if I ever come back». She never did come back.” And so Stanisława took care of Masza.
Chana Fajnsztajn did not survive the war – she was most probably shot in Ponary. Stanisława took care of Masza and of a number of family heirlooms, such as photos, cutlery with carved initials of Masza's father, and other small objects.
Stanisława arranged for the so-called Aryan documents for Masza. From then on, the girl was officially Stanisława's daughter – Maria Butkiewicz, born on 12 May 1939. In order to avoid any suspicion and conflict with her neighbours, Stanisława moved out of the flat and took Masza to live in the countryside, at her relatives' house. First, they lived with her brother, Józef Butkiewicz, in a small village near Podbrodzie, and later – in the household of Stanisława's cousins, the Markowski family, in Niemenczyn.
Masza survived the war. Together with Stanisława, she moved to Węgorzewo, and then to Zielona Góra. Growing up, she always knew about her real origins. In 1958, she married and took her husband's name – Kowalski. In the following years, she remained in close contact with Stanisława, she often visited and took care of her.