Last in a three-part series

Former assistant nurse Mika Nishiyama served out a 12-year prison term, having been convicted of killing a patient by pulling out a respirator tube, before finally being released in August 2017.

While in prison, she wrote more than 350 letters to her parents claiming her innocence. Reading through the letters, the investigative reporting team at the Chunichi Shimbun, along with Nishiyama’s defense team, came to suspect that she might have some kind of disability that could have led her to make false confessions.