SUKHUMI, September 10 (RAPSI) - Investigators have begun questioning possible witnesses to the murder of a Russian diplomat in Abkhazia, the republic's security services told RIA Novosti on Tuesday.

The investigation reports that three 9 mm shell casings and a homemade explosive device were found at the scene of the crime.

Dmitry Vishernyov, first secretary at Russia's embassy in the regional capital Sukhumi, was killed by a gunshot to the head in the garage of his home at about 8:30 am on Monday, local police said. His wife was wounded in the attack and is now in the hospital, a law enforcement source said.

Abkhazia de facto broke away from Georgia following a war in 1992-93, and was formally recognized as independent of Tbilisi by Russia in 2008 following a conflict in another breakaway Georgian region, South Ossetia. Russia has been a close ally of Abkhazia in its drive for independence and has a security assistance agreement with Sukhumi.

Political violence is not unknown in Abkhazia. In February 2012, unknown assassins tried to kill the republics President Alexander Ankvab in a gun and bomb attack on his motorcade.