A Russian journalist said Friday that law enforcement officials searched his apartment and carted off computers that contained draft chapters of two books he was writing about President Vladimir Putin.

Vladimir Pribylovsky said he was told the seizures were part of an investigation into the unsolved slaying of a former senior official of the main successor agency to the KGB.

But Pribylovsky, who runs a Web site critical of the Kremlin, said he suspects officials were really interested in finding out what he planned to publish about Putin.

"I believe that they wanted to read what I was writing," he told The Associated Press.

The Moscow prosecutor's office declined to comment.

Pribylovsky said he had previously written about the killing of Col.-Gen. Anatoly Trofimov, a former deputy head of the Federal Security Service shot in 2005 by a masked gunman outside his Moscow home. The author said that he agreed to remove some materials relating to the case from his Web site three months ago at the request of officials.

The working titles for the books are "Putin's Comrades," and "Operation Successor," said Pribylovsky, who was working on the latter with Yuri Felshtinsky, a historian and author living in the United States.

Felshtinsky told the AP that his co-author's computers contained "a huge volume of information" on ranking government officials.

"There is a lot of very interesting and important information, which might be lost because they could drag on the investigation, any investigation, for some years now, and the idea was to publish the book before the election," Felshtinsky said.

Felshtinsky co-authored a book, "Blowing Up Russia," with Alexander Litvinenko, who died in a London hospital in November after being poisoned with radioactive polonium-210. The book alleged that Russian security forces had played a role in a series of mysterious bombings of apartment buildings in Russia in 1999 that killed more than 300 people. The explosions were blamed on Chechen rebels and served as a key reason for the Kremlin to launch the second war in Chechnya.

After Litvinenko's death, Felshtinsky said, he and Pribylovsky continued to collaborate on "Operation Successor," parts of which have been published in various periodicals. But the two authors halted all direct contacts out of concern for Pribylovsky's safety.

"Pribylovsky is in a much more dangerous position than I am because I am in the United States and he is in Russia," Felshtinsky said.

British prosecutors have named Andrei Lugovoi, a Moscow businessman and former FSB agent, as their chief suspect in Litvinenko's murder.

The search of Pribylovsky's apartment took place the same day that Lugovoi held a news conference to protest his innocence, and to claim there was evidence the British secret services were involved in the slaying.