Warsaw, 2 April 1946. Judge Stanisław Rybiński, delegated to the Commission for the Investigation of German Crimes, interviewed the person named below as a witness, without an oath. Having been advised of the criminal liability for making false declarations and the obligation to speak the truth, the witness testified as follows:
| Name and surname | Jan Kubalski |
| Parents’ names | Wacław and Zofia née Miodek |
| Date of birth | 11 July 1901 |
| Place of residence | Warsaw, Słowackiego Street 45a, flat 5 |
| Occupation | Chief of Municipal Transport Office |
| Education | Faculty of Civil Engineering, Warsaw University of Technology |
| Religious affiliation | Roman Catholic |
| Criminal record | none |
During the German occupation I was acting as the head of the road construction department in the MZK [Municipal Transport Office]. I didn’t have the opportunity to meet Ludwik Leist, the city starost. The Municipal Transport Office wasn’t really connected to the Stadthauptmannschat and Leist.
A certain Dürrfeld was directly supervising the municipal enterprises – an individual particularly harmful for the Poles as an SS man. Dürrfeld, in theory Leist’s subordinate, held a higher rank in the party hierarchy and in fact was acting independently from Leist; he was his opponent, as far as I know. In cases of significant events such as arrests and similar incidents in the Trams [Tram Enterprise], Dürrfeld usually showed up, however from 1941 he was working on the corner of Marszałkowska and Świętokrzyska Street, in the PKO house. Dürrfeld punished the tram workers for the slightest offenses. In 1940, workers in the main workshop were going to go on Italian strike to support their demands for higher salaries. Dürrfeld came with gendarmeries, arrested chiefs Niepokojczyski and Synek, who were then deported to Auschwitz, as well as the department’s head Rostek. Niepokojczycki and Rostek died in the camp. Along with the directors, more than a dozen workers were taken to Auschwitz too. Few of them came back. Another incident occurred in 1942. Then senior controller Ernest Maikrantz found out from one of his informants that workers were using rail scraps for their own needs. Maikrantz reported this to Alertz, who issued an ordinance and Maikrantz conducted arrests and deportations with his approval. Whether Dürrfeld came then, I don’t know.
Dürrfeld’s direct subordinate – the German chief of the MZK – was Hipolit Alertz from Oberhausen (Rhineland). Alertz, bearing a title of engineer, was a poor specialist, albeit conceited. His ordinances did a lot of harm to the Municipal Transport Office. In his drastic rulings Alertz used other people, but the ideas for all the repressive measures came from him. Throughout his tenure, constant arrests and deportations to Treblinka, Auschwitz and Majdanek were carried out. Alertz hated Poles, although he was kind on the surface.
Ernest Maikrantz came from Wuppertal in Rhineland. He was Alertz’s main tool. He handled Jewish and Polish prisoners brutally, beating them with whips. He was drafted into the army in the summer of 1943.
Hanz Bollenbach – chief of police and Werkschutz – took an active part in the arrests, harassing the workers and the bystanders captured near the trams (for example for riding on the sides of the train, etc.), whipping and slapping them.
All the Germans mentioned above came from the Rhineland, supported each other and knew each other well.
Alertz was transferred to Łódź from 1 January 1944, and with his successor, Post, the policies loosened up a bit.
The report was read out.