Allies of slain Russian opposition leader Boris Nemtsov have dismissed the versions presented by Russian investigators into the killing.
Vladimir Milov, a co-leader of Nemtsov's political party RPR-Parnas, told RFE/RL's Current Time television program on March 9 that it was “undisputable and clear” that Russia’s secret services were “involved in this murder."
"I believe the government has very obvious motives to incite fear in the ranks of the opposition,” he added.
Another party leader, Ilya Yashin, told the AFP news agency, “The official version of the inquiry is more than absurd. In my opinion, it is the result of a political order from the Kremlin.”
"Our worst fears are coming true,” he added. “The hitman has been arrested but the commander will remain free."
Yashin earlier said on Twitter, "Investigators' nonsensical theory about Islamist motives in Nemtsov's killing suit the Kremlin and take [President Vladimir] Putin out of the firing line."
Nemtsov, a longtime critic of Putin, was shot four times in the back late on February 27 as he walked with his girlfriend along a bridge just meters from the Kremlin, sending shockwaves through the country's opposition and prompting an outpouring of international condemnation.
A Moscow court on March 8 ordered five suspects -- all from Russia's volatile North Caucasus -- held in custody until April 28.
Two of them, both of Chechen origin -- Anzor Gubashev and Zaur Dadayev -- were charged with involvement in the shooting.
The three other suspects include Gubashev's brother, Shagid, Ramzan Bakhayev, and Tamerlan Eskerkhanov.
Bakhayev and Esterkhanov are reportedly related to Dadayev.
Officials said Dadayev and the two Gubashevs were arrested in Ingushetia on March 7 and the other two in suburban Moscow early on March 8.
A sixth man was reported to have killed himself during a standoff with police late on March 7 in the Chechen capital, Grozny.
The court said Dadayev, one of the men charged, admitted involvement.
On his Instagram account on March 8, Kadyrov said he had been an officer in an Interior Ministry unit in Chechnya.
He also defended Dadayev, saying he is "a true Russian patriot" and a pious Muslim who was shocked by cartoons of the Prophet Muhammad in the French satirical magazine Charlie Hebdo.
Nemtsov had condemned the deadly January attack by Islamist gunmen on the Paris office of Charlie Hebdo.
Investigators have suggested that Nemtsov’s killers wanted to destabilize Russia, which is facing its worst standoff with the West since the Cold War over Ukraine.
But they were also probing the possibility he was assassinated for criticizing Russia's role in the Ukraine conflict or his condemnation of the Charlie Hebdo attack.
Russia's Investigative Committee said it had evidence that Nemtsov had received threats "in connection with his position" on the Paris attack.
But Yashin told AFP that Nemtsov had "never spoken negatively about Islam" and had merely criticized the Islamist militants who gunned down 12 people at the French weekly’s offices.
Also on March 9, an official website published a decree signed by Putin granting Kadyrov a high state medal.
Kadyrov, among other Russian officials and celebrities, was awarded the Order Of Honor for "professional achievements, public activities, and many years of diligent work."
Putin has relied on Kadyrov to maintain control over Chechnya, where rights activists accuse him of condoning abuses and creating a climate of fear to keep an Islamist insurgency and separatism in check.
On January 19, hundreds of thousands of people joined an official rally in Grozny against the cartoons.
Addressing the crowd, Kadyrov criticized Western governments for allowing other media to reprint the caricatures.
Also in January, Nemtsov accused Kadyrov of violating Russia's criminal code by infringing journalists' activities.
"Everybody is already sick and tired of Ramzan's threats, but he is certain that Putin will not let anyone touch him, so he is growing increasingly brazen every day," he wrote on Facebook.
With reporting by AFP and Reuters