Two prominent lawyers were among 15 public figures arrested in Hong Kong on April 18 for their alleged roles in organizing last year’s political protests, prompting the Hong Kong Bar Association to criticize the move as one that “could be perceived as interference,” in contravention of Hong Kong’s Basic Law, the local Constitution.

The police arrested 15 people on suspicion of organizing or participating in unauthorized public assemblies in Hong Kong last summer and fall when pro-democracy demonstrations were at their height. The arrests marked the biggest roundup of prominent opposition figures in recent memory.