An investigative panel under the state-backed Riken research institute said Friday that the debunked STAP cells generated by one of its scientists were likely created instead from embryonic stem cells.

It also said it identified two further instances of research misconduct by the lead author of the reports, Haruko Obokata.

The panel "concluded STAP stem cells . . . were derived from ES cells, based on examinations of the remaining samples," Isao Katsura, director general of the National Institute of Genetics and head of the seven-member panel, told reporters in Tokyo.