history
From 《汉书·路温舒传》: 路温舒 (Lu Wenshu, Western Han dynasty) submitted a memorial decrying judicial torture, arguing that confessions extracted under torture led to convictions where prosecutors made the crime so heavy that 'even if Gao Yao (皋陶, the legendary judge) heard the case, he would still feel death was insufficient punishment' - 虽咎繇听之，犹以为死有余辜. Today the phrase is reserved for the most heinous crimes.
usage
Always pejorative and very strong - used for murderers, traitors, mass killers. Don't apply to ordinary wrongdoing.
