Russian investigators have identified a man who sold the gun used to kill campaigning journalist Anna Politkovskaya in 2006, Kommersant daily reported on Tuesday.
Businessman Vladimir Nabatov modified an air pistol to fire live bullets and then sold the gun to Dmitry Pavlyuchenkov, a former senior police officer on trial for organizing the contract killing.
It is not clear whether Nabatov is in police custody.
The suspected gunman, Rustam Makhmudov, was arrested in May last year in his native Chechnya.
Politkovskaya was found shot dead outside her apartment on October 7, 2006. She won fame by exposing human rights abuses by the Russian army and its allies in Chechnya.
Pavlyuchenkov has accused London-based Chechen separatist leader Akhmed Zakayev and dissident oligarch Boris Berezovsky of ordering the killing. Both men have denied the accusation