Warsaw, 24 May 1946. Investigating Judge Halina Wereńko, delegated to the Commission for the Investigation of German Crimes, heard the person named below as a witness. Having been advised of the criminal liability for making false declarations and of the significance of the oath, the witness was sworn and testified as follows:
| Name and surname | Leonard Karol Sempoliński |
| Names of parents | Jan and Cecylia, née Barczyńska |
| Date and place of birth | 4 November 1902, Warsaw |
| Occupation | shopkeeper and photographer |
| Education | secondary |
| Place of residence | Warsaw, Walecznych Street 27, flat 9 |
| Religious affiliation | Roman Catholic |
| Criminal record | none |
During the Warsaw Uprising, having been caught in town, I stayed at Podwale Street 19. I remained there until the Germans left, so until 2 September 1944.
On 13 August at about 4.00 p.m., I saw from the window on the third floor of the house at Podwale Street 19 how a tank seized by the insurgents came from Kilińskiego Street. The tank was not armed, it did not have a canon and was of an old type. The insurgents put a flag on it, and the youths, girls, scouts – about a hundred people – gathered around the tank and led it as a trophy, yelling enthusiastically. Some 200 people, mainly the young people who had led the tank, were killed in the explosion that took place opposite the house at Kilińskiego Street 5, as the tank stopped in front of a barricade, which was going to be removed from the way. Their remains were scattered around the nearby rooftops and balconies. A human head fell into my room. When the smoke cleared, I saw fragments of human bodies on neighboring rooftops and balconies. We collected the remains and buried them, among other places, in the courtyard at Podwale Street 19.
As I learned later, the Germans had come in three tanks to the barricade in Krasińskich Square, and after a brief action two of them retreated, taking the crew of the third tank – the one which exploded before my very eyes. Seeing that the tank was not damaged and its engine was still working, the insurgents enthusiastically took it beyond the barricade, treating it as a prized trophy. The tank turned out to be mined.
I will submit a photograph which I took in May 1945.
This incident was witnessed by Stanisław Pęcherski, who observed it from the basement of the house at Podwale Street 19 (he currently resides in Warsaw at aleja Wojska Polskiego 20, in the Żoliborz district).
The report was read out.
On 13 June 1946 witness Leonard Karol Sempoliński reported again to the Commission and submitted a photograph of the remnants of the tank about which he had testified above. The photograph is appended to this report.