Alexander Torshin, who headed the parliamentary commission of inquiry into last year’s September 2004 hostage siege, stressed that terrorists were mainly to blame for the killings of 331 hostages, half of them children.
But he had harsh words for regional police and intelligence services and said police had ignored orders to impose tight security at schools at the beginning of the school year.
"The Interior Ministry, the FSB (security service) and other government organs basically did not carry out preventive, organisational, operative and other steps to uncover and halt the criminal activities of the terrorist groups," Torshin told deputies in an interim report on his probe on Wednesday.
"Let's not blame everything on international terrorists. Let's start with ourselves, enforce order in our own home, then maybe they will feel less comfortable," he said.
The bloodbath in the North Caucasus town occurred during an attempt by Russian security forces to end a tense stand-off with a group of heavily-armed Chechen separatist gunmen and free the hundreds of hostages they were holding at the school.
Relatives of the hostages killed say officials have failed to reform the region's government and fear their loss will not be the last.
They and journalists like opposition writer Anna Politkovskaya mock Torshin's commission as an attempt to cover up the corruption and incompetence that failed to stop the rebels from reaching the school, and led to so many deaths.
Torshin was clearly sensitive about the criticism. But he said it was negligence that stopped police from preventing the disaster, rather than corruption.
Relatives of the victims fear
their loss will not be the last
In limited criticism of officials' conduct, he pointed out "mistakes and shortcomings" that had hastened the tragedy.
"The camp where the rebels (prepared the attack) was only 70 metres (yards) from the road. We saw it. We were there. It was only 550 metres from a village, they did not hide themselves," he said.
Individual police officers had failed to guard the school, despite specific orders from interior ministry chiefs, or find the rebels beforehand, he said.
Poor coordination had handicapped attempts to end the siege.
"You can see how our police worked from the fact that the bandits had a plan of the school, while the police had to hunt for (a plan of the school) for a long time," he said, urging further reform.
But he insisted that police could be forgiven for failing to control all aspects of an explosive situation.
"It is the terrorists who came to attack a school who are the main people to blame. They came to destabilise the situation in the North Caucasus," he said.