South Korean prosecutors want to question a U.S. scientist about his work with a team led by disgraced stem-cell researcher Hwang Woo-suk, South Korean media reported on Friday.
University of Pittsburgh scientist Gerald Schatten was one of several co-authors of a 2005 paper from Hwang's team on producing tailored embryonic stem cells.
Hwang's troubles mounted when Schatten distanced himself from Hwang's team last year after charging the South Korean researcher with unethical practices in human egg procurement for their work.
The paper has since been debunked and a Seoul National University investigation panel said it was based on data that was intentionally fabricated.
Prosecutors would like to question Schatten about whether he had been aware of the fabrication, South Korea's YTN television said quoting officials.
"An email signed by Prosecutor Hong Man-pyo who heads the special investigation has been sent to Professor Schatten requesting cooperation in confirming facts in this case," a prosecution official was quoted as saying by the South Korean Internet news agency Edaily.
Prosecution officials could not be reached for comment.
Hwang's research had raised hopes because it seemed to hasten the day when genetically specific tissue could be grown from embryonic stem cells to repair damaged organs or treat diseases such as Parkinson's.
South Korean prosecutors raided Hwang's home on Thursday and a government committee said separately his team violated ethical practices in procuring human eggs.
The raid came a day after a prosecution source said prosecutors had widened their criminal investigation into Hwang's team to see whether they had breached a bioethics law by illegally purchasing human eggs.
Prosecutors have already launched a criminal probe of the team on suspicion the members fraudulently used state funds, which is punishable by up to 10 years in jail.
South Korea's bioethics law allows for therapeutic cloning for embryonic stem-cell research, but bans human cloning.
It prohibits the commercial trade in ova or sperm, providing punishment of up to three years in jail for brokers and up to two years for donors.
Hwang has blamed junior researchers for the fabricated data.
