The Investigative Committee
Kurman Ismailov, deputy mufti of the southern region, was killed Monday evening while traveling in his car in the capital of North Caucasus Federal District of Pyatigorsk.
The blast was caused by a bomb equivalent in strength to four kilograms of TNT, the Investigative Committee said in a statement Tuesday. Earlier reports had classified the explosion as an accident.
Investigators feel the murder "could be linked to the professional activity of Ismailov," or as the result of a personal argument, the statement said.
He was detained last year on suspicion of illegal explosives possession, but was shortly released without being charged.
Stavropol region mufti Muhammad Rakhimov told Interfax that no one had threatened Ismailov.
"He would try to smooth out all conflicts, and he would never get into conflicts," Rakhimov said, according to the report.