Confusion reigns over the identity of the group who seized the school in North Ossetia, taking hostage more than 1,000 children and their parents and teachers.
BBC News Online Russian affairs analyst
The official Russian version says that the hostage-takers were a multinational group linked to the radical Chechen rebel commanders Shamil Basayev and Doku Umarov, funded by al-Qaeda.
Though some hostages are reported to have recognised Doku Umarov from pictures shown them by investigators, little other evidence has otherwise been produced to support the claim.
Russia says there were 30 hostage-takers
Officials initially claimed there were nine or 10 Arabs among the hostage-takers - possibly in an attempt to back up their allegation of al-Qaeda involvement - but some surviving hostages have said they saw no Arabs in the school.
The only surviving hostage-taker so far shown on television spoke Russian with an accent typical for the North Caucasus.
Western experts say that allegations of a direct link between al-Qaeda and Chechen rebel leaders remain unproven - though it is well-known that the rebels receive funding from foreign Muslim sympathisers and that Arab commanders occupy key positions in the rebels' ranks.
The official Chechen rebel leader, Aslan Maskhadov, has condemned the seizure of the school.
In a statement on Sunday, he described the Beslan attackers as "madmen" - but implicitly acknowledged Chechen involvement, by saying that acts of terror were carried out by people whose desire for revenge against acts of brutality by Russian troops had driven them out of their senses.
Earlier, Mr Maskhadov's envoy in Europe, Ahmed Zakayev, said he had been told by the former Ingush leader, Ruslan Aushev, who tried to negotiate an end to the crisis, that the hostage takers were not themselves Chechen.
Shamil Basayev regards Russian civilians as legitimate targets
Interestingly, the Kommersant newspaper on Friday lent some support to this theory, saying investigators suspected that the ringleaders - or at least those who took part in the negotiations - were Magomet Yevloyev (an ethnic Ingush fighter close to Basayev), Vladimir Khodov (from North Ossetia) and an unnamed Russian, possibly one of Basayev's bodyguards.
If it turns out to be true that Chechens were not running the Beslan operation on the ground, this will be a new development.
It will follow on from the attack on the Ingush interior ministry in June, in which many or most of the estimated 200 militants who took part are thought to have been Ingush rather than Chechen.
It could be a sign of growing support for the Chechen cause - or for the radical Islamism which the most powerful rebel leaders now espouse - in neighbouring parts of the North Caucasus.
The pro-rebel Kavkaz Center website suggested that Mr Khodov was the leader of an Ossetian militant Islamist group, or Jama'at, though it could be deliberately trying to promote the idea of holy war spreading out from Chechnya. (While most Ossetians are Christian or pagan, some are Muslim.)
Whether this is true or not, the Beslan attack helps to confirm that Chechen radicals have effectively sidelined the moderate Aslan Maskhadov, even though he remains officially their leader.
Russian officials may well be right to point the finger of blame at Shamil Basayev, who carried out the first Chechen mass hostage-taking in the southern Russian town of Budyonnovsk in 1995 and who claims to have masterminded the seizure of a theatre in Moscow in 2002, which led to 129 deaths.
While the Budyonnovsk raid was unplanned the Moscow operation was carefully organised, like the latest hostage-taking in Beslan School Number One, where it is thought weapons and explosives may have been stored weeks in advance.
Unlike Maskhadov, Basayev regards Russian civilians as legitimate targets - though never before has he chosen children as his primary victims.