Investigators have extended their 5-month-old probe into Radio Liberty correspondent Andrei Babitsky, who disappeared for weeks after being detained by Russian forces in Chechnya, his colleagues said.

Babitsky is not allowed to leave Moscow while he is under investigation, and his identification documents and passport have been confiscated.

His lawyer, Genri Reznik, said the authorities are dragging out the case to keep Babitsky from returning to Chechnya, where his coverage was often critical of the Russian military campaign.

"The case is dragging on forever," said Radio Liberty colleague Andrei Sharogradsky. "For him, the hardest part is that he can't work [in Chechnya], this is very painful." Investigators have extended the probe until Aug. 25.

Babitsky was detained by secret service agents in the breakaway republic in January for not having proper accreditation, then disappeared for weeks before resurfacing in Russian custody in neighboring Dagestan. He was eventually released on condition that he not leave Moscow.

Many journalists and Western governments cited the case as a sign that President Vladimir Putin is cracking down on independent media.