Originally Posted by DBS.US

FYI:Only Voluntary, Permanent Tattooing is Forbidden
The prohibition of tattooing throughout the halakhic literature deals only with personal, voluntary tattooing. With respect to the reprehensible practice of the Nazis who marked the arms of Jews with tattooed numbers and letters during the Shoah [Holocaust], the Shulhan Arukh [the authoritative 16th-century code of Jewish law] makes it clear that those who bear these tattoos are blameless: "If it [the tattoo] was done in the flesh of another, the one to whom it was done is blameless" (Shulhan Arukh, Yoreh De'ah 180:2).