Two men were charged on Sunday in connection with the murder of Russian opposition figure Boris Nemtsov last month in Moscow, court officials said.
Anzor Gubashev and Zaur Dadayev, who were arrested on Saturday, appeared in court along with three other suspects, who are yet to be charged but are being treated as suspects, court spokesperson Anna Fadeyeva said.
The three suspects were named as Tamerlan Eskerkhanov, Ramzan Bakhayev, and Shagid Gubashev, a brother to Anzor Gubashev.
Both men charged are from the impoverished Caucuses region in southern Russia, Alexander Bortnikov, the head of Russia's Federal Security Service, said on state television on Saturday.
The presiding judge told the courtroom that Dadayev has admitted to being involved in the killing.
"Dadayev's involvement in committing this crime is confirmed by, apart from his own confession, the totality of evidence gathered as part of this criminal case," Judge Natalia Mushnikova said, according to Reuters.
Dadayev, who will be held in custody until April 28, was reported to have previously served as part of a police unit in Chechnya.
Albert Barakhayev, a security official in the region of Ingushetia, told Russian media Dadayev served for roughly 10 years in a police battalion for the Chechnya's interior ministry, according to Reuters.
Russian news agency Interfax reported that a man who blew himself up with a grenade on Sunday in Chechnya's capital, Grosny, was wanted by police in connection with the Nemtsov murder.
Nemtsov, a former deputy prime minister turned outspoken critic of Kremlin, was shot dead on the evening of Feb. 27 on a bridge near Red Square.
His murder shocked Russians, with tens of thousands marching last weekend in memory of the slain politician.
Nemtsov had been scheduled to lead the march, which had been organized to protest against Russia's actions in Ukraine.
The Kremlin has denied any involvement in the killing, with President Vladimir Putin promising to personally oversee the investigation.
Russia's Interfax news agency quoted a source close to the investigation as saying that the pair were arrested after police discovered the getaway vehicle the killers used, according to the BBC.
Telephone records and evidence collected inside the car has reportedly been the focus of investigations, while surveillance footage was also said to provide "sufficiently clear" images of the suspects.
On Facebook, opposition activist Ilya Yashin called on the authorities to make all the evidence public.
"Often in such high-profile cases it's often only about detaining the perpetrators, thus enabling the authorities to get a nice picture on TV," he wrote. "But if those who ordered the murder are able to escape responsibility, the practice of political murders will definitely go on."