National security police have summoned the father of an activist wanted for his involvement in “Hong Kong Parliament”, a group deemed subversive by authorities, to “assist in an investigation”, the Post has learned.

A source said that police had asked the father of Alan Keung Ka-wai to report to Tin Shui Wai Division Police Station on Wednesday morning to help with the investigation into his son, a Canada-based activist.

“[We] expect the investigation to wrap up around noon,” the source said.

Alan Keung is among 15 activists who were each slapped with a HK$200,000 (US$25,477) bounty last month for their involvement in an overseas election organised by “Hong Kong Parliament” in May.

Police earlier accused the group, founded by wanted self-exiled activists Elmer Yuan Gong-yi, Victor Ho Leung-mau, Fok Ka-chi and Choi Ming-da, of attempting to subvert state power by promoting “self-determination” and formulating a so-called Hong Kong constitution.

Keung was also the chairman of the Taiwan-based advocacy group, Hong Kong Democratic Independence Union.

Four members of the union based in the city, aged 15 to 47, were arrested by national security police last month for conspiring to subvert state power.