Their announcement all but ends the fraud investigation into one of three cloning breakthroughs claimed by Hwang Woo-suk. His two other groundbreaking experiments are still being investigated at Seoul National University where he worked before resigning in disgrace last week.
The latest news was one more disappointment to the scientific world, which had viewed Hwang's achievements as holding great promise for treating injuries and diseases.
One stem cell scientist bemoaned the most recent development. Joseph Itskovitz, director of the department of obstetrics and gynaecology at Rambam Medical Centre in Haifa, Israel, said: "The bottom line is that it's a major disaster to our whole field because the expectations were so high and now we are back to square one."
In the experiment now found to be fraudulent, Hwang had claimed in a paper published in May in the journal Science that he had created 11 colonies of human embryonic stem cells genetically matched to specific patients.
An investigative panel at the university reported last week that Hwang had faked the research on nine of the stem cell lines. On Thursday, it confirmed that he also fabricated his research for the two remaining cell lines as well.
Roe Jung-hye, the university's dean of research affairs, said: "The panel couldn't find stem cells that match patients' DNA regarding the 2005 paper and it believes that Hwang's team doesn't have scientific data to prove that [such stem cells] were made."
The university said that it expected to finish all work on that case by next month and have findings on two others: Hwang's claim in 2004 to have created the world's first cloned human embryo and extracted stem cells from it; and his research published in Nature last August claiming to have produced the first cloned dog.