Paul Klebnikov, an American journalist for Forbes magazine who investigated the murky dealings of tycoons and gangland figures in the new Russia, was shot and killed Friday night by unknown assailants, according to Russian news agencies.

Klebnikov, 41, was shot four times near his office about 10 p.m. and died in an ambulance summoned to the scene, the Interfax news agency reported. Echo Moskvy radio said police found shell casings from two handguns, indicating that there were at least two attackers.

Klebnikov, a senior editor, joined the magazine in 1989. He went to Moscow full time in April to launch a Russian-language edition, which in its debut issue identified the richest Russians and reported that more billionaires hailed from Moscow than any other city in the world.

The slaying was the first contract-style killing of an American in Moscow in years but part of a trend of violence against journalists here. The Moscow correspondent for the Afghan service of Radio Free Europe/Radio Liberty was stabbed and critically injured outside his apartment last week, and a colleague from the Turkmen service was beaten at his home in April. The advocacy group Reporters Without Borders last year called Russia "one of the world's deadliest countries for journalists."

Although known for his investigative reports, Klebnikov told a friend over dinner Monday that he was optimistic about Russia and wanted to highlight its progress. "He was excited to be back in Russia and was saying that he was particularly interested in doing positive stories about the place, that he felt there were a lot of positive signs of what was happening in the country," said Mark Franchetti, a correspondent for the Sunday Times of London.

Klebnikov's wife was with him at the dinner but planned to return to New York the next day. She stayed behind with their children when Klebnikov relocated to Moscow. The only story in progress that Klebnikov mentioned to Franchetti was a feature on the culture clash between the British and Russians at the new TNK-BP oil company joint venture.

Steve Forbes, president and editor in chief of the magazine, said in a statement that Klebnikov "was a superb reporter -- courageous, energetic, ever-curious." He said Klebnikov had "embraced the opportunity to become the first editor of Forbes Russia. He knew Russia well. It was a country he loved deeply."

Klebnikov wrote a Forbes article in 1996 on Russian magnate Boris Berezovsky, calling him a "powerful gangland boss" behind whom "lies a trail of corpses." Berezovsky, an influential adviser at the time to then-President Boris Yeltsin, sued the magazine in Britain, calling the article a "series of lies."

Klebnikov went on to write a book on Berezovsky titled "Godfather of the Kremlin: Boris Berezovsky and the Looting of Russia," a prosecutorial-style account of the magnate's rise to riches and power. The book said Yeltsin's Russia was ruled by a "kleptocracy" and was "one of the most corrupt regimes in the world." Berezovsky later fell out with Yeltsin's successor, Vladimir Putin, and fled to Britain to avoid what he said were politically motivated corruption charges.

Berezovsky withdrew the lawsuit last year after Forbes acknowledged that there was no evidence the tycoon had ordered the 1995 murder of television journalist Vladislav Listiev or any other killing. Forbes said at the time that it made no financial settlement to end the suit.

When Klebnikov became editor in chief of Forbes Russia, with a circulation of 40,000, he promised gripping coverage of the country's new business elite. At a news conference launching the publication, according to the Associated Press, he said, "Here people fly and fall with staggering speed."

Paul Klebnikov moved back to Moscow to launch a Russian-language edition of Forbes.