The head of the Russian human rights group, Glasnost Foundation, said yesterday he would file a complaint against a Kremlin official over the treatment of the Radio Free Europe correspondent, Andrei Babitsky.
Russian military officials said they exchanged the journalist, who had been arrested on January 18th by federal forces in Grozny, for several Russian soldiers who were being held by Chechen rebels.
Babitsky's whereabouts and condition are unknown and his colleagues and wife fear for his life.
"We have sent the Russian prosecutor general a request to open a criminal case against Sergei Yastrzhembski [spokesman for acting the Russian President, Mr Vladimir Putin] on three charges: non-denunciation of the crime, falsification of the evidence, and kidnapping," Mr Sergey Grigoriants, director of the foundation, said.
Mr Yastrzhembski is the Kremlin's spokesman on the Chechen war and was the first to announce that Babitsky had been swapped for Russian prisoners of war.
The foundation also requested Russia's public prosecutor to look into "the complicity of acting President Vladimir Putin in this criminal affair," Mr Grigoriants said.
Russia's defence minister, Mr Igor Sergeyev, claimed yesterday that the war in Chechnya would be over within a month. The first round of presidential elections is due to take place on March 26th and a declaration of victory in Chechnya would ensure the election of Mr Putin.
Fighting is now concentrated in the Vedeno and Argun gorges, the key access points to the mountainous terrain in southern Chechnya where most of the rebels are now based.
Russian forces claim to have killed 600 Chechen rebels last week but this has not been independently confirmed.