A human rights activist says the lawyer representing a prominent Bahraini blogger held by authorities has been detained himself just days after alleging his client had been tortured while in police custody.

Jim Loughran, a spokesman for the group Frontline Defenders, said Sunday that lawyer Adbul Aziz Moussa was picked up by authorities on Thursday.

Moussa is defending detained blogger Mohamed Hassan. Hassan also worked as an assistant to various foreign journalists visiting Bahrain.

Loughran said Moussa’s arrest comes after he posted messages on Twitter claiming Hassan suffered abuse while in police custody.

Bahrain, home to the U.S. Navy’s 5th fleet, has faced 18 months of unrest between the Sunni-led monarchy and its majority Shiite population. The government has started a crackdown on dissent.