Russian judge Nataliya Mushnikova said Zaur Dadaev (pictured above) confessed his involvement in the fatal shooting of Kremlin critic Boris Nemtsov. A second suspect, Anzor Gubashev, was also charged with organizing and carrying out the murder on February 27.

The former deputy prime minister of Russia and prominent critic of Russian President Vladimir Putin died after he was shot in the back four times within sight of the Kremlin. The only witness was Nemtsov's girlfriend, Ukrainian model Anna Duritskaya.

Ukraine conflict report

The men were two of five suspects in the case who were marched to a Moscow court on Sunday. Among the suspects was Gubashev's younger brother Shagid and two men identified as Ramzan Bakhayev and Tamerlan Eskerkhanov - all of whom have been detained in custody.

On Saturday, close associates of Nemtsov said that shortly before his death the opposition figure had been gathering evidence to prove the Kremlin was lying about its role in the ongoing conflict in eastern Ukraine. Colleagues from the opposition movement Solidarnost now want to publish Nemtsov's findings next month.

Putin denounced the death of his high-profile critic as a tragedy and a "provocation" and promised to personally oversee an investigation into the incident.

Intimidation

Vocal Putin critic Alexei Navalny, however, accused the Kremlin of ordering Nemtsov's assassination to intimidate the opposition amid Russia's mounting economic problems.

Navalny was freed from a detention center in western Moscow on Friday after serving 15 days for handing out leaflets for a demonstration planned for last Sunday. The rally became an impromptu mourning march for Nemtsov, with some 50,000 people attending.

Since Putin came to power in 2000, a number of prominent opposition figures have been murdered, including journalist Anna Politkovskaya and activist Natalya Estemirova.

ksb/sms (AFP, AP, Reuters, dpa)