There was a plan in 1943 to drop Welrods into German-occupied territories for the mass assassination of Schutzstaffel (SS) and Gestapo officers and soldiers within a one-month period by resistance units. This plan was possibly delayed or called off in the aftermath of Operation Anthropoid, the assassination of Reinhard Heydrich by Czech resistance forces.[1] In the wake of his assassination, an estimated 13,000 civilians were arrested and interrogated, 5,000 civilians murdered in German reprisal killings and the villages of Lidice and Ležáky destroyed.

https://en.wikipedia.org/wiki/Welrod