A Japanese man has pleaded guilty to murdering nine people after contacting them on Twitter, in a high-profile case that has shocked the country. Dubbed the "Twitter killer", Takahiro Shiraishi was arrested in 2017 after body parts were found in his flat. He told a court in Tokyo on Wednesday that the allegations against him "are all correct". But his lawyers argue that his charges should be reduced because his victims apparently gave consent to be killed.