A top Muslim cleric in Russia’s Tatarstan province was shot dead and another wounded by a car bomb in two separate attacks apparently related to the priests’ criticism of radical Islamists, investigators said Thursday.

Russia’s Investigative Committee said that Valiulla Yakupov, the deputy to the Muslim province’s chief mufti, was gunned down Thursday on the way out of his house in Tatarstan’s regional capital, Kazan.

Chief mufti Ildus Faizov was wounded in the leg after an explosive device ripped through his vehicle in central Kazan, Tatarstan investigator Eduard Abdullin told The Associated Press.

Investigative Committee spokesman Vladimir Markin told Russian news agencies that his agency is looking into the clerics’ professional activity as a possible cause of the attacks.

Both clerics were known as critics of radical Islamist groups that advocate a strict version of Islam known as Salafism. Faizov was also criticized by media in Tatarstan for allegedly profiting on tours he organized for Muslim pilgrims.

The rise of Salafism in this Volga River province has been fueled by the influx of Muslim clerics from Chechnya and other predominantly Muslim provinces of Russia’s Caucasus region where radical Islamists have for years been involved in a violent confrontation with secular authorities.

In 2008, a court in Kazan sentenced a radical Islamist leader to life in prison for organizing a group that planned terrorist attacks in Tatarstan. Sixteen of his followers received prison terms ranging from three to 12 years.

More than a half of Tatarstan’s population of 4 million is Sunni Muslims. Tatars converted to Islam more than a thousand years ago, and the province became an important center of Muslim learning and culture under Tatar-Mongol rulers that controlled Russia and parts of Eastern Europe.