According to reports by several Arab media outlets, police arrested Mohamed al-Nimr on Tuesday in Al-Awamia, a town situated in the Qatif region in Saudi Arabia’s Eastern Province.
Mohamed al-Nimr was released after a few hours on the same day, the reports said.
He had told Tasnim on Sunday that the death sentence handed to his brother, Sheikh Nimr Baqir al-Nimr, has been referred to King Salman’s office for a final decision.
Saudi criminal court had earlier referred Sheikh Nimr’s case to an appeals court, where the verdict was upheld in early March.
Sheikh Nimr was detained in July 2012 following demonstrations that erupted in Qatif region. He is accused of delivering anti-regime speeches and defending political prisoners.
His arrest has sparked widespread protests in the Arab country, leaving several people dead.
Last October, Sheikh Nimr’s family reported that a Saudi judge has found him guilty of “sedition” and sentenced him to death.