In a setback to the investigation in the murder of famous investigative journalist Anna Politkovskaya, Russian Prosecutor General’s Office on Thursday freed two suspects arrested recently.

“Alexei Berkin and Oleg Alimov have been freed from custody,” RIA Novosti news agency reported, quoting a source close to the investigation in the murder.

Russia’s Prosecutor-General Yury Chaika had announced on Monday that 10 suspects had been arrested for involvement in the murder, which included former and serving security and police officers.

Leading Russian business daily Kommersant reported on Thursday that announcement by Chaika on Monday about solving the murder of Politkovskaya was “apparently premature”.

“The investigators have released one of the suspects, while another has an ironclad alibi--he was in prison at the time of murder. The third one was detained under a different case,” the paper said.

A fierce critic of President Putin’s policy in Chechnya and human rights abuses, Politkovskaya was shot dead in an elevator of her apartment block in a contract-style killing in Moscow on October 7, 2006. She was working for liberal daily Novaya Gazeta. Her murder triggered a worldwide outrage.

Chaika said on Monday her murder had been ordered by someone living abroad in order to discredit Putin and destabilise Russia.

Citing continuing investigation, he refused to give the name, but his remarks were interpreted as a reference to Russian tycoon Boris Berezovsky currently living in London in political asylum.

Russia has unsuccessfully been seeking Berezovsky’s extradition from Britain on charges of money-laundering and fraud.