KAZAN, Russia -- Police in Kazan, the capital of the Russian republic of Tatarstan, have launched investigations into an explosion that killed a man on November 20.
Andrei Sheptitsky of Russia's Investigative Committee told journalists that the explosion took place in front of an apartment block.
The explosive device killed 39-year-old Alfred Sharafutdinov.
He had been convicted in the past for illegal arms and explosives possession.
According to the victim's relatives, he had been drinking for at least two weeks before the incident.
Sheptitsky rejected initial reports that Sharafutdinov might have been connected with Islamic extremist groups.
Investigators say they have not ruled out the possibility that the incident was a suicide.
With reporting by Interfax