Outspoken Catholic leader and activist Cardinal Joseph Zen Ze-kiun has been arrested by Hong Kong’s national security police, along with former opposition lawmaker Margaret Ng Ngoi-yee and singer Denise Ho Wan-sze for allegedly colluding with foreign forces, according to sources.

The three, who were detained on Wednesday, were among five trustees of the 612 Humanitarian Relief Fund, which was set up to offer financial assistance to those involved in anti-government protests in 2019 and which came under the intense scrutiny of authorities over the past year.

A fourth trustee, former adjunct associate professor Hui Po Keung, was arrested by national security police on Tuesday as he was about to catch a flight to Germany, a source said.