RUSSIA: A collective shudder has gone through the ranks of Russia's tycoons following the questioning by prosecutors of the country's richest man - Mr Mik- hail Khodorkovsky.
Mr Khodorkovsky, head of oil giant Yukos Oil, was taken in for questioning the day after a senior Yukos shareholder, Mr Platon Lebedev, was arrested.
Also arrested, in a murder investigation, was Yukos security chief Mr Alexei Pichugin.
Newspaper photographs of the tycoon, worth an estimated £8 billion, having to hand his identity card to police at the entrance to the prosecutors' office has reminded Russia's rich about the fragility of their position.
Prosecutors are investigating the soft underbelly of Russia's tycoons - the means by which they made their fortunes in the first place.
Many of the country's super-rich owe their fortunes to questionable deals in which they bought state-controlled assets, such as oil and gas fields, for a fraction of their true value in the 1990s.
Now, it appears, prosecutors want to know more about such deals.
The tycoons - nicknamed Oligarchs by Russians because of their political clout - had thought they had put such problems behind them.
In 2000, President Vladimir Putin had appeared to strike a deal with the tycoons - after first sending in the investigators.
The mightiest tycoon, Mr Boris Berezovsky, fled the country in 2000 rather than face investigators - and is currently fighting an extradition battle from London.
Another tycoon, Mr Vladimir Gusinsky, was at the centre of an international storm when his TV station, NTV, passed into state control and he also fled Russia.
And finally Mr Putin forced gas giant Gazprom, Russia's biggest company, state-owned but in practice a law unto itself, to accept one of his loyalists as its new chairman.
But having dealt with the biggest of the oligarchs, Mr Putin later that year offered the rest an olive branch.
At a famous round-table meeting, he appeared to promise the tycoons that they - and their fortunes - would be left alone, providing they stayed out of politics and paid their taxes.
And recently, the tycoons, feeling more secure, have been branching out, hoping to win influence and respect abroad.
Some have joined the boards of prestigious western cultural institutions - Mr Khodorkovsky himself has forged a link with Britain's Somerset House.
And another tycoon Mr Roman Abramovich, controller of oil company Sibneft, last week bought London's Chelsea football club.
But it appears no such deal exists - and on the evidence of this week, the prosecutors have long memories. The Khodorkovsky investigation has widened, with raids in Moscow to seize the Yukos computer server company records.
And Mr Lebedev's bad heart condition has not stopped him being incarcerated in Moscow's Lefortovo prison.
Mr Khodorkovsky has come out fighting, claiming the investigation is punishment for his support of two opposition parties, Yabloko and Union of Right Forces.
Elections are coming in December and some think the Kremlin wants to ensure tycoon money does not support rival parties.
"Everything that is currently happening is, in my opinion, outside the boundaries of the law," he told a Moscow newspaper yesterday.
"That is, in form everything is legal, but in essence it is absolutely not."
He is not alone: "This is a political purge ahead of the elections, to put pressure on the political opposition," said Yabloko leader Mr Grigory Yavlinsky.
But he also made what looked like a plea to Mr Putin to call off the dogs.
"We are putting up a barrier: what was before 2000 is history," he said.
"Let us live under different laws after 2000.There are forces that do not want to acknowledge this agreement."