Samsung Group leader Jay Y. Lee appeared at the South Korean special prosecutor's office on Monday for questioning as part of a wider investigation into an influence-peddling scandal that could topple President Park Geun-hye.
Lee is accused of pledging 43 billion won ($37.31 million) to a business and organisations backed by Park's friend, Choi Soon-sil, in exchange for support for a 2015 merger of two Samsung companies.
Park, Lee, Choi, and Samsung Group have all denied bribery charges.
Proving illicit dealings between Park or her confidantes and Samsung Group is critical for the special prosecutor's case that ultimately targets Park, analysts say. Park was impeached by parliament in December.
Lee arrived at the prosecution office in southern Seoul early on Monday in a black sedan, dressed in a dark blue suit and tie and flanked by Samsung Group officials and his lawyer.