In autumn of 1939, the Germans carried out mass arrests of dozens of Poles, including teachers, local activists, judges, parliamentarians, editors and bank employees, however some were later released. 47 Poles arrested in Tomaszów Mazowiecki, including Tomaszów's mayor, were also imprisoned in Piotrków. Further mass arrests of hundreds of Poles were carried out in January, March, June and August 1940. Among Poles arrested in March were 12 teachers and students of secret Polish schools. On June 29, 1940, the Germans carried out a massacre of 42 Poles from the prison in the Wolborski Forest in the northern part of the city. Among the victims were 14 students aged 17–18, eight reserve officers, and people of various professions, including pharmacists, an architect, railwayman, teacher, farmer and local secretary. 121 Poles from the local prison were deported to the Auschwitz, Gross-Rosen and Dachau concentration camps in June 1940. Many Poles, who were born or lived in the city, were murdered by the Russians in the large Katyn massacre in April–May 1940.