A former Chechen police officer who admitted taking part in the murder of Russian opposition activist Boris Nemtsov "likely confessed under torture", a member of the Kremlin's human rights council said Wednesday.
Zaur Dadayev allegedly confessed and was charged with murder but has now insisted to the council's Andrei Babushkin that he is "innocent" and only made the admission under duress.
"There are reasons that lead us to believe Zaur Dadayev confessed under torture," Babushkin told AFP after a visit to the suspect's Moscow prison cell on Tuesday.
"We cannot confirm that he was tortured as we are not investigators but we did find numerous wounds on his body," said Babushkin, who was swiftly rapped over the knuckles by investigators for meddling in their probe.
The shooting of Nemtsov, a former deputy prime minister who became an outspoken critic of President Vladimir Putin, near the Kremlin was the highest-profile killing of an opposition leader during Putin's 15 years in charge.
Dadayev, a former deputy commander in a special Chechen police unit, was charged by a Moscow court on Sunday with the murder alongside Anzor Gubashev, who worked for a private security company. The two men and three other suspects were remanded in custody.
A court in Moscow heard the men were being probed under a section of the Russian criminal code relating to murders carried out for financial gain, in a sign investigators believe Nemtsov's murder was a hit.
'I am innocent'
Babushkin said Dadayev claimed he had made the confession under duress after being arrested in the North Caucasus region of Ingushetia last week, alleging that he spent two days manacled and with a sack over his head.
"They shouted at me all the time, 'You killed Nemtsov, didn't you?'. I said, 'no'," Babushkin reported Dadayev as saying.
The suspect said he had eventually admitted to the killing to secure the release of an ex-colleague, Ruslan Yusupov, who was detained alongside him.
"They said that if I confessed they would let him go. I agreed. I thought I would save him and they would bring me to Moscow alive," Dadayev was quoted as saying by Babushkin.
"I thought that I would be brought to Moscow and would be able to tell the court the full truth. That I am innocent," Dadayev reportedly said.
Rights groups have consistently condemned widespread abuses in Russia's notorious prison system and during interrogations by officials.
Russia's powerful investigative committee condemned Babushkin's statement as breaking the law and said that he and a colleague who visited Dadayev would be questioned over possible "interference in a criminal case".
"They will be subject to an investigation aimed at clarifying their motives," investigators said in a statement.
Babushkin is one of some 60 unpaid members of the Kremlin council that includes writers, scientists, journalists and rights activists. The group meets Putin once a year and has been previously criticised as mere window-dressing for the authorities.
Council chief and presidential adviser Mikhail Fedotov describes his job as "the rock of Sisyphus" after the myth in which a rock is ceaselessly rolled to the top of a mountain, but prides himself on several victories such as the release of the jailed Pussy Riot punk rockers.
Nemtsov, 55, was shot four times in the back on February 27 as he walked along a bridge in central Moscow with his girlfriend.
The killing sent shockwaves through the opposition, which accuses Putin of steadily suppressing dissent and alleges that the Kremlin was behind the murder of one of its last outspoken critics.
Investigators have said they were looking into the possibility that the former deputy prime minister was killed over his support for French satirical magazine Charlie Hebdo, which published images of the Prophet Mohammed and was attacked in January.
But close allies of the prominent activist in Russia's marginalised opposition dismissed that claim as "absurd".
Ramzan Kadyrov, the Kremlin-loyal strongman leader of Russia's Muslim Chechnya region, also decried Dadayev's arrest, describing him as a "real Russian patriot".
Authorities have also said they are probing the possibility that Nemtsov was murdered for criticising Russia's role in the Ukraine conflict or as part of a plot to destabilise the country.
Opposition newspaper Novaya Gazeta on Wednesday published a report into the investigation alleging that Nemtsov's killing was organised in Chechnya and that the Kremlin had uncovered a "hit list" listing the names of other Russian opposition figures, including former business tycoon Mikhail Khodorkovsky.
Kremlin spokesman Dmitry Peskov ridiculed claims that top officials had seen a list of any potential targets.
The press secretary for Khodorkovsky -- who currently lives in exile in Switzerland -- said Wednesday that she had found a mourning wreath propped outside the door of her Moscow apartment.