Prosecutors investigating the stem cell scandal say they plan on re-summoning Professor Hwang Woo-suk and his former assistant Kim Sun-jong this week.

A prosecution official said the two key figures were being re-summoned due to a host of unresolved questions regarding two fabricated research papers.

The prosecution is expected to focus on grilling Hwang over whether he knew of a supposed swapping of stem cells before MBC TV raised speculation over his research in an investigative documentary last November.

Prosecutors also want to know whether Kim conspired with other researchers to switch the stem cells.

The prosecution is considering unveiling the interim results of its investigation around the end of this month.