Belarussian police have detained four people in connection with the July slaying of the American editor of Forbes magazine's Russian edition, Interfax reported.

The killing of Paul Klebnikov (search), 41, has compounded concerns about the safety of journalists in Russia and about the violence often used to settle scores.

Two of the four currently held by Belarusian security services were identified by the Belarusian police as ethnic Chechens Kazbek Dukuzov and Musa Vakhayev, according to the report.

Speculation on the motive has focused on Klebnikov's writing about the Russian business world. In the spring, Forbes published a list of Russia's 100 richest people, which could have drawn unwanted attention to people sensitive about the source of their wealth.

But some commentators have said a Chechen link was also possible, pointing to Klebnikov's book based on his interviews with Khozh-Akhmed Nukhayev (search), a former deputy prime minister in the Chechen separatist government, which was published last year.

The book, "Conversations With a Barbarian," cast Nukhayev and other Chechen rebels in a sharply negative light.

A Moscow court had already sanctioned the arrest of Vakhayev, 40, a resident of the Chechen town of Urus-Martan, Interfax reported earlier this month.

Two Chechens arrested in September for allegedly participating in the killing were later released.

The Committee to Protect Journalists (search) said earlier this month in Washington that there have been 11 contract-style murders of reporters since Russian President Vladimir Putin took office in 2000. None has been solved.