Five men from the rebellious Caucasus region of southern Russia were brought Sunday before a Moscow court where two were charged for their alleged roles in the killing of Kremlin critic Boris Y. Nemtsov.
One of the charged suspects, former Chechen police commander Zaur Dadayev, pleaded guilty to the murder charge, the official Tass news agency reported in an urgent dispatch.
"Dadayev's involvement is confirmed by his confession," Judge Natalya Mushnikova of the Basmanny district court was quoted as announcing after the arraignment.
Formal charges were also brought against Anzor Gubashev, who was arrested Saturday in the Ingushetia region of the Caucasus. Three other suspects were ordered held for further investigation, court press secretary Anna Fadeyeva told reporters.
Officials from the Federal Security Service and from the Caucasus region of Ingushetia on Sunday identified three men arrested in the case and alluded to a fourth. But it was only when the suspects were delivered for their first court appearance that the fifth man's implication in the killing was alleged.
"The Investigative Committee is requesting that five suspects involved in the murder of Boris Nemtsov be arrested. The investigation is ongoing," Russian Investigative Committee spokesman Vladimir Markin said via Twitter as the men were brought under intense security to the courthouse.
Under Russian law, a court must approve holding suspects without charges within 48 hours of their arrest. Prosecutors sought and received a nearly two-month extension of custody, until April 28, for all five suspects while the investigation continues.
The three men held without charges were identified as Khamzat Bakhayev, Tamerlan Eskerkhanov and Shagit Gubashev.
Reports by the official Tass and Sputnik news agencies shed little light on a possible motive for the Feb. 27 slaying of Nemtsov, a former first deputy prime minister once seen as a possible president of Russia before the rise of the current Kremlin leader, Vladimir Putin.
Dadayev and Gubashev were detained Saturday while traveling in Ingushetia, where they were visiting relatives who moved there from their native Chechnya in the 1960s, Ingushetia Security Council chief Albert Barakhayev told Tass.
Tass quoted Barakhayev as saying that a brother of Gubashev was detained later Saturday, and Sputnik reported that the number of suspects in custody was four. Neither news agency identified a fourth person detained, nor did they mention the fifth brought to court.
Interfax news agency quoted an unnamed Chechen security officer as saying that another suspect in Nemtsov's killing blew himself up with a hand grenade as police moved in to arrest him at his apartment in Grozny, the Chechen capital.
Dadayev served in Chechnya's northern police battalion for a decade, Barakhayev said. The Gubashev brothers worked in private security, he added.
Chechnya, a predominantly Muslim and purportedly autonomous republic of Russia, has been under heavy military and federal security occupation since two secessionist uprisings were quelled in the 1990s. Chechnya is under the rule of a Moscow-installed governor, Ramzan Kadyrov.
Kadyrov propounded just hours after Nemtsov was gunned down as he crossed a bridge with his Ukrainian girlfriend in the shadow of the Kremlin that the slaying was the work of Western security forces trying to discredit Putin or destabilize Russia.
Other Kremlin-allied politicians and analysts have suggested the contract-style killing might have been carried out by Muslim fundamentalists enraged by Nemtsov's criticism of the Jan. 7 attacks on the Paris office of Charlie Hebdo, a satirical magazine that had published cartoons that offended Islamists.
The arrests of the suspects with Chechen roots can be seen as bolstering either of those theories on motive, although Nemtsov allies have been skeptical about the reliability of an investigation being directed by Putin loyalists.
Nemtsov was hated by the Chechen leadership now overseeing the republic for his biting criticism of Kadyrov, said Gennady Gudkov, a former Federal Security Service officer who heads another opposition political alliance in Russia.
Dadayev's experience as a deputy commander in Chechnya's security forces suggests that Nemtsov's killing might have been ordered by the Kadyrov administration, Gudkov told The Times.
"The killing could have been a kind of a ritual present to the Kremlin akin to ancient barbaric examples of slain enemies' heads brought to a king on a platter," Gudkov said, adding that there are reports Dadayev has been awarded the Russian national Order of Valor, personally bestowed by Putin.