MOSCOW — Two Chechens, one a police officer who fought Islamic insurgents and the second a security guard, were charged in a Moscow court on Sunday in connection with the killing of Boris Y. Nemtsov, a leading Kremlin critic, while three other suspects were jailed pending further investigation.

Judge Nataliya Mushnikova of Basmanny District Court said that the officer, Zaur Dadayev, had confessed to involvement in the killing and that other evidence confirmed his participation, Russian news agencies reported, but no further details were available. The second suspect charged, Anzor Gubashev, pleaded not guilty.

Despite the court appearances, neither the court nor Russian law enforcement agencies presented coherent pictures of the case thus far, including the roles played by the suspects or any motive they might have had.

Mr. Dadayev and Mr. Gubashev, whose arrests were announced on Saturday by Russia’s top law enforcement official, are believed to be the two directly involved in fatally shooting Mr. Nemtsov on Feb. 27.