What's the bribery scandal for which Samsung heir received 2.5 yrs in jail?

Samsung's billionaire heir Lee Jae-yong was sentenced to 2.5 years in jail on Monday in retrial of a bribery scandal. Lee assumed Samsung's leadership when his father Lee Kun-hee was hospitalised in 2014 and later died. Lee actively provided bribes and asked the then South Korean President Park Geun-hye to use her power to help his smooth succession at Samsung.