A Japanese scientist accused of manipulating stem cell research is urging the institute she works for to reinvestigate her case.

Dr. Haruko Obokata is affiliated with Japan’s Riken institute. She became a star after she identified a revolutionary method of producing stem cells.

Obokata faces accusations she falsified images and data published in the journal Nature. She has admitted making several errors in her articles, but denies any attempt to falsify data.

In a letter to Riken, Obokata says she was anxious to complete the articles before someone else took the lead in her field. She adds she was also under pressure from colleagues.

An internal investigation by Riken concluded that Obokata’s research papers had been falsified.