MOSCOW - The killing of Russian opposition figure Boris Nemtsov within sight of the Kremlin has exposed rarely seen tensions between different camps inside President Vladimir Putin's system of rule.
No outsiders can know with any certainty what is happening behind the red-brick walls of the Kremlin, but some of Nemtsov's associates say his shooting is being used by one faction to send Putin a message that they are unhappy and need to be reckoned with.
That would represent a challenge to the foundations of Putin's 15-year-old rule, built on a rigid pyramid of power and the assumption of unshakeable loyalty.
"I think that perhaps Putin, even completely sincerely, was bewildered and even afraid," Vadim Prokhorov, Nemtsov's lawyer, said of the hours after the Feb. 27 shooting.
"Because if you can do that next to the Kremlin, then is it not possible to do it along the route of the (presidential) motorcade?" he told Reuters.
Feeding a mood of frenzied speculation in Moscow, Putin this week cancelled a planned trip to Kazakhstan without explanation. A Kazakh official said Putin was ill, while the Kremlin said he was fine and working as usual.
Who is on which side in this rivalry, or even that such a rivalry exists, is impossible to establish with complete confidence because no one has publicly acknowledged any serious differences between camps.
Yet analysts point to signs of tensions between, on one side, the powerful head of Russia's Chechnya region, Ramzan Kadyrov, and on the other, the Russian state security agencies which are Putin's closest associates.
Nemtsov, a 55-year-old former deputy prime minister who had become a vocal critic of Putin, was shot dead as he walked home with his girlfriend after dining next to Red Square. He was the most prominent of a string of Kremlin critics to be killed since Putin came to power; in many cases the gunmen have been jailed but the masterminds remain unidentified.
Many of Nemtsov's supporters said the president stood to gain by removing a relentless critic. Russian officials denied involvement and Putin called the killing a shameful tragedy.