According to the Russian Criminal Code, in absence of a prisoner exchange treaty, a convict can be extradited on the basis of a mutually acceptable written agreement between authorized bodies in Russia and the country in question, the ministry said in a statement.
"Kaloyev could serve his prison sentence in Russia," the ministry said. "In order to initiate the extradition procedures, he should first submit his written agreement to do so."
Kaloyev lost his family in an air crash in July 2002, when a Tu-154 plane owned by Bashkirian airlines collided with a DHL-owned Boeing over Germany's Lake Constance. Sixty-nine people, including 45 Bashkir children flying to Spain on vacation, and two Boeing pilots, were killed.
German investigators said the accident was largely due to negligence on the part of Skyguide, and partially the fault of the two Russian pilots.
Peter Nielsen, a Skyguide air traffic controller, was stabbed to death on February 24, 2004 near his house in the Swiss town of Kloten. Vitaly Kaloyev was arrested in a local hotel a day later.