Zakharov and Babakekhyan were detained on July 7, 2006 in Marbella.
Spain will extradite to Russia on Friday another suspect in the 2002 contract killing of Magadan regional Governor Valentin Tsvetkov.
Martin Babakekhyan will be airlifted to Moscow from Madrid in the evening guarded by Russian Interpol officers and bailiffs.
Babakekhyan’s accomplice Alexander Zakharov was extradited to Russia last August.
Governor Tsevtkov was shot dead on October 18, 2002 in a central Moscow street. In 2003 the office of the Russian prosecutor general said the crime had been exposed. Two suspects Sergei Filippenko and Artur Anisimov were arrested and another five, including Zakharov and Babakekhyan, were declared wanted.