It's my knowledge that a lot of special police units encountered this situation. While there are certainly specific anecdotes, this was more a general trend.

Ordinary Men by Christopher Browning details the initial hesitance in committing acts of genocide by members of Reserve Police Battalion 101. This was an outfit of older-age men responsible for domestic police due to their less capable physical condition. For this reason, the responsibility of committing genocide on the ground-level fell onto their laps. There were numerous cases of men opting not to participate. In many cases, commanding officers were understanding and didn't raise issue with it. Also described by Browning is the eventual social pressure and sociological perspective involved in actually committing the genocidal acts based on peer pressure that perhaps was felt by each footsoldier simply due to the nature of the uniform.