Members of the battalion conducted roundups and deportations to Treblinka and Majdanek death camps as part of Aktion Reinhard, but on several occasions they also committed mass murders, including the Józefów Ghetto massacre with 1,500 victims, and the Miedzyrzec Ghetto massacre of late 1942.[8] The men of the Reserve Police Battalion 101 worked hand-in-hand with the Trawniki men from Ukraine, already since August 1942 committing war crimes in a string of other locations in Poland including Łomazy, Radzyń, Łuków, Końskowola (massacre at the hospital), Komarówka, Tomaszów, Serokomla, Talczyn and Kock, among others.[8][9]