I'm familiar with some of their activities, specifically those related to the Norsk Hydro plant. They were able to disable the plant's ability to produce heavy water (thus hindering Nazi atomic research) without killing a single person, but it seems that they were willing to kill if required. This was demonstrated when saboteurs sank the SF Hydro, the ferry carrying the remaining heavy water. They ended up killing 4 German soldiers and 14 Norwegian crew and passengers.
I'm familiar with some of their activities, specifically those related to the Norsk Hydro plant. They were able to disable the plant's ability to produce heavy water (thus hindering Nazi atomic research) without killing a single person, but it seems that they were willing to kill if required. This was demonstrated when saboteurs sank the SF Hydro, the ferry carrying the remaining heavy water. They ended up killing 4 German soldiers and 14 Norwegian crew and passengers.