The leader of Musavat's branch in the town of Massali, Xasay Safaroglu, told RFE/RL on June 28 that police went to Yadigar Sadiqov's home one day earlier and took him to police station.
Sadiqov was charged with attacking and beating a man in Massali.
Sadiqov remains in custody.
Interior Ministry spokesman Orxan Mansurzade told RFE/RL that Sadiqov's arrest has nothing to do with his political activities and requested that RFE/RL not "politicize the case," which he described as "mere hooliganism."
Musavat, Azerbaijan's oldest political party, has been in opposition to the ruling New Azerbaijan Party since 1993.