The government-funded Riken institute announced Thursday that it will not reinvestigate the controversial papers on so-called STAP cells, finalizing its conclusion that their main author, stem cell scientist Haruko Obokata, is guilty of research misconduct.

Riken also formally recommended withdrawing one of the two papers Obokata wrote with a team of Japanese and U.S. scientists that were published in the British journal Nature in January.

"I understand that (Riken's) investigative panel has reached the conclusion by carefully considering the matter," Riken President Ryoji Noyori said in a statement. "Based on its report, we have decided not to conduct a reinvestigation, have notified (Obokata) of our conclusion and have recommended one of the papers in question be withdrawn."