[MOSCOW] A Russian court on Sunday charged two men with the murder of opposition activist Boris Nemtsov, including a former police officer from Chechnya who confessed to his involvement in what investigators said was a contract killing.
Four others denied any connection to the killing of Nemtsov, who was shot four times in the back on February 27 while walking with his girlfriend along a bridge near the Kremlin in a brazen assassination that has sent shivers through the country's opposition.
Interfax news agency quoted a law enforcement source as saying that a sixth suspect threw a grenade at police who came to arrest him in the Chechen capital Grozny and killed himself with another grenade on Saturday.
In Moscow, heavily armed masked police marched the five handcuffed suspects through hallways packed with journalists and into two separate courtrooms where they were ordered to be held for around two months pending the investigation.
According to documents read out in court, the accused are charged under a section of the Russian criminal code relating to murders carried out for financial gain, Interfax reported.
The charges also involve extortion and banditry. Investigators said they were still seeking others who may have been involved.
However, as in a string of other killings of Russian opposition figures, officials have yet to shed light on who might have ordered the late-night murder of the 55-year-old Nemtsov, a fierce critic of President Vladimir Putin.
Zaur Dadayev, a decorated former deputy commander in a Chechen police unit born in 1982, and Anzor Gubashev, 31, who worked for a private security company in Moscow, were arrested on Saturday in Ingushetia, which neighbours Chechnya.
They were both charged with murder but Gubashev denied involvement.
"The participation of Dadayev is confirmed by his confession," said presiding judge Nataliya Mushnikova, according to state news agencies.
Chechen leader Ramzan Kadyrov said he was baffled by the arrest.
"I knew Zaur Dadayev as a true Russian patriot... He was one of the bravest and worthiest soldiers of his regiment," Mr Kadyrov said on Instagram.
Court spokesman Anna Fadeyeva told the RIA Novosti news agency that the other three men were still only suspects at this stage.
They are Gubashev's younger brother Shagid, Ramzat Bakhayev, 45, and Tamerlan Eskerkhanov, 34.
The men are all from the volatile northern Caucasus region where Russia has fought two devastating wars against Chechen separatists and where security forces continue to clash with Islamist insurgents.
"The suspects denied their involvement in this crime but investigators have proof of their involvement," a representative for the probe told the court.
RUSSIA 'CROSSED THE LINE'
However no information emerged as to the possible motive behind the killing of the former prime minister turned charismatic opposition leader who was one of the last outspoken opponents to Mr Putin.
Nemtsov's allies believe his assassination was a hit ordered by the top levels of government determined to silence dissenters. The allegation has been strenuously denied.
The murder in one of the most heavily policed parts of the Russian capital sent shockwaves through an opposition that has seen several Kremlin critics killed in recent years and that accuses Mr Putin of steadily suppressing independent media and opposition parties.
Nemtsov's daughter Zhanna Nemtsova, in an interview with CNN from Germany, said the murder was obviously "politically motivated".
"I think that now Russia has crossed the line after this murder, and people will be frightened to express their ideas which contradict... the official standpoint."
Her comments echo those heard from Kremlin critics such as Alexei Navalny, who accused "the country's political leadership" of ordering a hit on Nemtsov.
Nemtsov, who had long complained of being followed and having his phone tapped, had spoken of his fear of being killed.
Mr Putin has described Nemtsov's killing as a tragedy that brought disgrace on Russia and vowed that everything would be done to bring to justice those who committed a "vile and cynical murder".
Many Russians say that even if Mr Putin was not directly involved he is still to blame for whipping up hatred against the opposition by regularly referring to them as a "fifth column" of traitors and spies - a message spread daily by all-powerful state media.
He first used the term "fifth columnist" - which originated during the Spanish Civil War and refers to subversive sympathisers with an outside enemy - after he ordered the annexation of Crimea in Ukraine last year, plunging relations with the West to lows not seen since the Cold War.
Investigators have suggested Nemtsov's killers wanted to destabilise Russia while Kremlin-loyal politicians have referred to a Western plot.
Investigators say they are also probing the possibility he was assassinated for criticising Russia's role in the Ukraine conflict or for his condemnation of the deadly January attack by Islamist gunmen on the satirical weekly Charlie Hebdo in Paris.
At the time of his death, Nemtsov was believed to be working on a study documenting the secret deployment of Russian troops in Ukraine, something the Kremlin denies doing.