Sources told RTHK on Thursday that national security police had taken in more family members of businessman Elmer Yuan for questioning.

He's among eight people living overseas who are wanted for alleged national security offences, with rewards of HK$1 million offered for information that leads to their capture.

Those who were questioned are said to be Yuan's ex-wife as well as their son and daughter. According to sources, officers were seeking information on whether they remained in touch with Yuan or have any financial dealings with him.

Last week, officers also took in Yuan’s other family members – including another of his sons Derek Yuen and his lawmaker wife Eunice Yung – for questioning.

Since the announcement of the rewards a month ago, relatives of suspects Nathan Law, Dennis Kwok and Mung Siu-tat are also understood to have been questioned by national security police.