By Stephen Dalziel BBC Russian Affairs Analyst

Questions surrounding the ending of the siege of the Moscow theatre last Saturday like:

• What was the gas which knocked out, and in some cases, killed, both hostage-takers and hostages?
• Did special forces get the dosage wrong?
• Why were hospital workers not told what the gas was?

How could there have been such a failure of intelligence which allowed 53 rebels to gather in the Russian capital with large amounts of explosive?

Why were their movements not tracked?

How could so many rebels have slipped through the security net which has been a feature of Moscow life since the second Chechen campaign began in September 1999?

These questions may have dropped out of public attention. But addressing them and taking action will be high on the agenda of the Russian President, Vladimir Putin.

Useful distraction

Security officers have reason to be worried. Their president is a career intelligence officer, and so knows the business from the inside.

This is not just post-Soviet Russia, this is Putin's Russia - and the inquiry will be carried out at the pace which Mr Putin sets.

The gas question will have suited Mr Putin very well. It has served as a distraction from the intelligence issues, and he would far rather deal with security questions in private.

Indeed, he has already shown during his presidency that he likes to take time to consider important decisions.

Immediately after the sinking of the Kursk nuclear submarine in August 2000 - a disaster handled in an appalling fashion by the Navy - there were calls for sackings of those responsible.

Gas has proved a distraction from intelligence issues

Mr Putin's immediate response was to do nothing - in public. Instead, he set about a thorough investigation behind the scenes, and over the course of the next few months there were discreet notices published by the Itar-Tass news agency about senior naval officers being moved to other posts, or retired.

This is what we can expect now, too. In a more democratic society than Russia, as soon as the news of the hostage-taking broke, there would have been calls for the sacking of the head of the security service, the FSB, and the interior minister, whose ministry is responsible for the police force, and the traffic police who man checkpoints on every road in and out of the Russian capital, and have the power to stop traffic anywhere at will.

Behind the scenes

No doubt in some societies there would have been calls for the president to fall on his sword, too.

But this is not just post-Soviet Russia. This is Putin's Russia. And the inquiry will be carried out at the pace which Mr Putin sets.

He would see no logic in sacking the heads of the security organs now: they presided over the mess which the lapses brought about, so let them sort it out.

The Russian authorities may be maintaining an appearance of solidarity at having seen off the threat.

But behind the scenes, searching questions are being asked of the security services. And in the weeks and months ahead, there will be changes of personnel in the FSB and the interior ministry.

And when the dust has settled, do not be surprised to learn that the head of the FSB, Nikolai Patrushev, or the Interior Minister, Boris Gryzlov, have been assigned to other duties.