The Riken Center for Developmental Biology’s deputy chief, who was also a co-author of retracted stem-cell research papers, apparently committed suicide in Japan. Yoshiki Sasai, 52, was found with a rope around his neck and later died in a hospital. There were reports that a suicide note had been left.

Sasai was a member of the Riken research team that in July retracted two research papers published in Nature in late January that claimed that mouse cells could be transformed into stem cells by using an acid bath. Riken officials have alleged that Haruko Obokata, also a co-author of the research articles, falsified data in the studies.