Degas sketched the suspects in the "Abadie affair," a lurid murder trial over the brutal killing of a grocer's boy and a newspaper vendor. Influenced by evolutionary debate, commentators on the trial immediately associated the guilty man's low forehead, pronounced jaw, and "animal snout... with a degenerate, lower form of humanity.

Head of a Criminal, Emile Abadie by Edgar Degas (1880-1881)