A former researcher under cloning pioneer Hwang Woo-suk says he saw Hwang produce and nurture eight stem cell lines.

Kim Sun-jong, who worked for Hwang before going to the University of Pittsburgh, told reporters in Pittsburgh Friday that he is fully convinced that Hwang had the stem cells.

Kim also admitted to manipulating photos by making eleven images out of two stem cells because six stem cells died in the process of growth.

He said he knows nothing about the alleged switch of stem cells involving MizMedi Hospital and that an investigation will clear things up in about 10 days.

Kim said he will cooperate with prosecutors in Seoul and in the investigation on Hwang's work as requested by his university.