SEOUL (Reuters) – Samsung Group heir Jay Y. Lee on Tuesday was summoned and questioned by prosecutors over a controversial 2015 merger of two of the group’s affiliates, Yonhap News Agency said.

Lee is in trials over charges that he bribed a friend of former President Park Geun-hye to seek support for the deal that helped tighten his grip on the group, as he was preparing to take over from ailing patriarch Lee Kun-hee.

The deal combined construction firm Samsung C&T (028260.KS) and fashion and theme-park operator Cheil Industries Inc into a merged entity. It was widely criticised by U.S. hedge fund Elliott Management and other investors who said Samsung’s family members pursued their own interest at the expense of minority shareholders.

A Samsung Electronics spokesman declined to comment. Prosecutors were not immediately available for comment.