Russia political mystery deepens
From Jill Dougherty
CNN Moscow Bureau Chief
Rybkin, allied with oligarch Berezovsky (left), has criticized Putin.
MOSCOW, Russia (CNN) -- The mystery surrounding the disappearance of a Russian presidential candidate has deepened with the launch -- and then cancellation -- of a murder probe.
Ivan Rybkin -- former speaker of Parliament and strong critic of President Vladimir Putin -- went missing on Thursday.
Rybkin's family and staff filed a missing persons report Sunday, and the FSB -- Russia's Federal Security Service -- launched an investigation.
On Monday morning, Moscow prosecutors announced a criminal case on charges of pre-meditated murder. But they canceled it almost immediately, saying there was "no basis" for such a case.
"We have no reasons to believe Ivan Rybkin was abducted or killed at the moment," Russian news agencies quoted a prosecutor's office official as saying.
A liberal, Rybkin is running as an independent in the March 14 presidential election -- which Putin is expected to win easily.
Rybkin's campaign said it lost contact with him Thursday night.
"He may have fallen, been robbed and killed, his body hidden. The other possibility is that it was an election trick, but it is not like him. The third option is linked to politics, but as far as I know he did not receive any threats," his election aide Ksenia Ponomaryova told Reuters.
His wife, Albina, said she found his shirt and some dishes in the sink when she returned home but no trace of her husband. She suggested that Rybkin may have been kidnapped.
Last week, in an open letter published in the Russian newspaper Kommersant, Rybkin accused Putin of being "the biggest oligarch in Russia."
"I am convinced Putin has no right to power in Russia ... and we have no right to be silent about it," Rybkin wrote.
He also accused the president of being allied with forces trying to control Russian business. Putin did not answer the charges.
Rybkin is a supporter of negotiations with Chechen separatists, an idea Putin vehemently rejected just last Friday following a subway bombing blamed on Chechen terrorists.
The bombing killed 39 people and injured more than 100 others. (Full story)
Rybkin, 57, was a national security adviser to former President Boris Yeltsin. He is one of six candidates running against Putin.
His poll ratings have hovered around 1 percent, and experts agree he has no chance of winning the race.
He did manage to collect 2 million signatures to put his name on the ballot, although the central election committee said it found numerous falsifications. He was certified as a candidate, however.
Rybkin is co-chairman of the Liberal Russia political party. Two of its parliamentary members have been killed under questionable circumstances.
Rybkin also is allied with Russian oligarch Boris Berezovsky, who now lives in London. Some opponents of Berezovsky have raised the possibility that he might be tied somehow to Rybkin's disappearance.
But Berezovksy told a Moscow radio station Sunday that he was "pretty sure" Rybkin was "alive and well," saying Rybkin's wife was told by officials that he was safe.