Law enforcement official also are looking into whether any of the suspects in the Antonov case also are responsible for the Sept. 24 assassination of Ruslan Yamadayev, a prominent Chechen military leader and politician, and attempted murder of Sergei Kizyun, a retired general, ITAR-TASS reported.
Vladimir Markin, a spokesman for Russia's Investigation Committee of the Prosecutor General's Office, said the arrests were made Tuesday.
Antonov and his guard, Alexander Komarov, were attacked in Moscow on March 11.
"Investigators do not rule out the detainees' involvement in other crimes, including the murder of Ruslan Yamadayev," Markin said.
The Russian news agency also reported Adam Delimkhanov, a member of the lower house of the Russian parliament, denied accusations he was involved in the murder of Yamadayev's brother, Sulim Yamadayev, another prominent Chechen military figure, in Dubai, United Arab Emirates, on March 28.
"They made a mountain out of molehill with the statement by a Dubai policeman," Delimkhanov said. "It's an inefficient statement by an inefficient Dubai policeman."
Notable deaths of 2014 [PHOTOS]