Warsaw, 25 February 1946. Acting investigating judge Halina Wereńko, delegated to the Commission for the Investigation of German Crimes in Poland, heard as a witness the person specified below. Having been advised of the criminal liability for making false declarations and of the importance of the oath, the witness was sworn and testified as follows:
| Name and surname | Karolina Mossakowska |
| Date of birth | 18 October 1900 in Błonie |
| Parents’ names | Józef and Rozalia |
| Occupation | tradeswoman |
| Education | elementary school |
| Place of residence | Błonie, Harcerska Street 6 |
| Religious affiliation | Roman Catholic |
| Criminal record | none |
My brother, Albin Aleksander Mossakowski, who had been a clerk in the Supreme Administrative Court before the war, was a merchant during the German occupation and lived in Warsaw at Ciepła Street 15, flat 17. As far as I know, my brother was not engaged in the underground movement.
On 4 or 3 December 1943, my brother left home and never came back. On 6 or 9 December, I don’t remember the exact date, I saw my brother’s name and surname on a poster notifying that about a hundred people had been executed. Where the executions had taken place at that time, I do not remember.
I did not manage to learn any details concerning my brother’s fate. The exact date of the arrest of my brother, or at least the date when he had left home, could be determined by the caretaker of the house in which my brother had lived at Ciepła Street 15, flat 17, on the corner with Krochmalna Street.
I don’t know the caretaker’s name.
The report was read out.