TOKYO (AP) — A senior Japanese scientist embroiled in a stem-cell research scandal has apparently committed suicide, police said Tuesday.

Yoshiki Sasai, who supervised and co-authored stem-cell research papers that had to be retracted due to falsified contents, was found dead Tuesday at the government-affiliated science institute RIKEN in Kobe, in western Japan, according to Hyogo prefectural police. Sasai, 52, was deputy chief of RIKEN’s Center for Developmental Biology.