South Korean prosecutors have indicted 10 individuals on suspicion of leaking memory chip manufacturing technology to Chinese chipmaker ChangXin Memory Technologies (CXMT), a move authorities say contributed to China’s rapid development of high-bandwidth memory (HBM), a key component for artificial intelligence computing.

The Seoul Central District Prosecutors’ Office announced Tuesday that five people—including a former Samsung Electronics executive and engineers—were charged and held in custody for violating South Korea’s industrial technology protection law. The remaining five were charged but released on bail.

Prosecutors stated that a former Samsung Electronics researcher, who was transitioning to CXMT, copied hundreds of proprietary DRAM manufacturing steps by hand. The notes detailed process recipes, including equipment specifications, sequencing, and yield optimization, which were later used by CXMT to reconstruct the manufacturing flow.

The investigation also revealed that CXMT obtained additional DRAM technology from SK Hynix via a supplier, further accelerating the company’s development in the HBM sector.