STAVROPOL, August 13 (RIA Novosti) – A senior Muslim cleric in Russia’s North Caucasus received a letter containing a torn photo of himself apparently shot with a bullet as investigators probe an earlier death threat made against him, the Prosecutor General’s Office said Monday.

The Interior Ministry said Thursday that police were investigating the initial death threat against Mukhammad Khadzhi Rakhimov, the mufti of the region of Stavropol.

On Wednesday, the mufti told police that he had received a letter containing a death threat. The ministry said a criminal investigation had been opened but did not provide any other details. The mufti has declined to comment on the incident.

Attacks on senior Muslim clerics have become increasingly frequent in Russia in recent years, especially in the volatile North Caucasus.

In late December, North Ossetia’s deputy mufti, Ibragim Dudarov, was murdered in the republic’s capital, Vladikavkaz.

Last August, Muslim cleric and prominent Sufi sheikh Said Atsayev, was killed in a suicide bombing in the turbulent North Caucasus republic of Dagestan.

Last July, the head mufti in Russia’s republic of Tatarstan, Ildus Faizov, was injured in a car bomb attack, hours after his former deputy was shot dead.