GROZNY, Russia, March 8 (UPI) -- The sixth suspect in last month's killing of Russian opposition leader Boris Nemtsov blew himself up as police surrounded his apartment in the North Caucasus on Saturday.
Beslan Shavanov, 30, attempted to escape his Grozny apartment by tossing a grenade at officers, blowing himself up, according to Russian media.
News of the standoff came at the same time Russian authorities said they had detained five other individuals suspected of killing Nemtsov.
One of President Vladimir Putin's most outspoken critics, Nemtsov was shot to death near the Kremlin on Feb. 28 as we walked across a bridge with his girlfriend. He had been scheduled to lead an anti-Putin rally in Moscow on March 1.
Putin denounced the killing Wednesday but on the same day said Russia faced "attempts to use the so-called 'color technologies' in organizing illegal street protests to open propaganda of hatred and strife on social networks ... The aim is obvious -- to provoke civil conflict and strike a blow at our country's constitutional foundations, and ultimately even at our sovereignty."
Putin blamed Nemtsov's killing on extremists who he said were trying to stir internal strife in Russia, but opposition figures have blamed the Russian president, saying Nemtsoz is merely the latest of Putin's opponents to be killed or imprisoned.
An estimated 70,000 people came out to mourn Nemtsov at the March 1 rally near the Kremlin.
Federal Security Service director Alexander Bortnikov said the other five suspects -- Anzor Gubashev, Zaur Dadayev, Ramzan Bakhayev, Shagit Gubashev and Tamerlan Eskerkhanov -- come from the southern portions of the North Caucasus, which since the 19th century has been the scene of sporadic rebellions against Moscow, including during two bloody wars in Chechnya during the 1990s and 2000s.