ACHING TO KNOW

The bodies of Beslan’s children lay in freshly dug graves when the most troubling questions of the deadly hostage-taking at Middle School No. 1 started to emerge.

On the roof of a five-story apartment building across from the school where 318 hostages died and about 700 others were wounded in September, residents found three large, empty tubes, a little more than 36 inches long, marked with red stripes and numeric codes. In Russia’s battle-scarred North Caucasus region, it didn’t take long to find someone who could identify them as the casings of a rocket-fired flamethrower projectile.

Had someone fired flamethrowers at a school full of captive children? Why?

Similar confusion surrounded the discovery outside the school of three casings from the enormous, 125-millimeter cannon of a T-72 tank.

Were any hostages alive when the tank pointed its gun at the school and opened fire?

A week from today, Russia will observe the first anniversary of the worst terrorist act in its history. But Beslan residents have made it clear that senior officials in Moscow, including President Vladimir V. Putin, are not welcome at the ceremonies -- not until it is certain that the authorities themselves bear no responsibility for the lives lost in the explosions and storming operation that ended the three-day ordeal in the Russian republic of North Ossetia.

The tragedy began when an estimated three dozen militants, calling for Russian troops to leave the neighboring republic of Chechnya, herded 1,128 students, teachers and parents into a stuffy gymnasium and wired it with makeshift bombs.

But what caused the deadly conflagration that ended the standoff remains unclear, and the doubts have loomed larger as time has passed. According to the official version, bombs accidentally exploded inside the school, touching off a fire that rushed through the gym and killed many of the hostages.

But numerous survivors believe that the furious gun battle between the hostage-takers and armed forces outside the school may have played a crucial role in igniting and spreading the blaze.

A confidential military prosecutor’s review of the siege obtained by the Los Angeles Times, along with interviews with former hostages and a government videotape of the carnage, suggests a chaotic operation with little or no communication among military units.

Grenades, tank shells and flamethrowers were fired into the school building, and an armored personnel carrier also opened fire, this evidence shows. An uncontrolled, unpredictable crowd of armed civilians was allowed to open fire at the school, complicating the question of who fired the first shot, and a botched firefighting operation may have led to 100 or more hostages being burned alive.

Moreover, the only surviving hostage-taker insists that the initial explosions were ignited when a sniper shot a militant whose foot was on the trigger.

“We ask questions, and they don’t answer,” said Susanna Dudiyeva, chairwoman of the Beslan Mothers Committee, which is leading the campaign for a full account of the conflagration.

“They tell us the prosecutor is looking into all this, and they say an expert analysis of the situation is underway.... They didn’t think the citizens would do things like searching for tubes. They didn’t think the citizens would present any particular demands to them at all,” she said. “Somehow, they must address our doubts and the information we’ve collected. If what the eyewitnesses are saying is the truth, then they must admit it’s the truth. And if they think they’re not telling the truth, then they must say why.”

Stanislav Kesaev, a member of the commission investigating the incident on behalf of the parliament of North Ossetia, said too many questions remained unanswered.

“What concerns me most is that I feel too many people, including in offices very high up, don’t want to search for the truth,” Kesaev said. “Because the truth is that they are not sufficiently professional, not sufficiently patriotic, not sufficiently civic-minded and, ultimately, not sufficiently decent.”

The questions are hard to answer, in part because most hard evidence disappeared when bulldozers hauled away the rubble and scraped the gymnasium floor clean the day after the siege ended.

Two months later, Murat Katsanov, a local driver, was at a dump outside town when he stumbled upon a pile of refuse that caused his hair to stand on end: clumps of human tissue and identity documents belonging to a hostage at the gym. It was wreckage hauled out of the school, he knew immediately. Or what was left after the crows and foxes got to it.

“I saw it myself, when they brought these excavators in, all kinds of vehicles, trucks. They loaded all of this aboard and took it out to the dump. Even without knowing all the details, we were absolutely shocked,” said Ruslan Tebiev, whose wife died while being held hostage. He had assumed the authorities were removing ordinary debris, not the possibly incriminating fragments of flamethrowers and tank shells. “If I’d have known they were carting away the evidence, I would have thrown myself under the wheels of the excavator myself.”

A year after the tragedy, Russian officials are no closer to explaining what happened than they were in the beginning. Even among hostages who were sitting almost next to each other in the gym, accounts often differ wildly. A federal parliamentary commission investigating the episode has neither released its findings nor given any indication of when it intends to do so.

A source close to the commission, who spoke on condition of anonymity, said a final report had been delayed, in part because of troubling unresolved questions about the use of flamethrowers and continuing doubts about the cause of the initial explosions in the gymnasium.

Russian Deputy Prosecutor General Nikolai Shepel, who is leading the investigation to determine whether law enforcement authorities were criminally negligent in their conduct of the operation, insisted that the evidence so far tended to rule out the possibility that the heavy weaponry wielded by government forces contributed to the death of any hostage.

“We’ve been questioning victims, witnesses, employees of the special services, specialists in mines and explosives ... and we are filtering what they have told us through the physical evidence so that we can establish a three-dimensional picture of what was happening at the scene,” Shepel said in an interview.

But Beslan residents began to have doubts about the objectivity of the inquiry when they handed over the flamethrower tubes to government investigators, not long after the siege, only to be told later that the tubes had been lost.

The government now acknowledges that it fired flamethrowers at the school but insists they were used only against any holed-up terrorists after all the hostages were dead. Whether hostages were still alive when the flamethrowers were fired, as some witnesses believe, and whether the flamethrowers caused the inferno are questions that lack answers.

For some Beslan residents, the idea that flamethrowers, and not the initial explosions, caused the blaze emerged when they approached the school after dark in the days after the siege and saw what they came to believe were hints of phosphorus, which is a telltale element of a napalm-type flamethrower.

“We saw it ourselves,” said Elbrus Tetov, editor of the Zhizn Pravoberezha newspaper in Beslan, whose 10-year-old son burned to death only moments after pushing another child out the gym window. “You would look at the school, you would look, say, at a corner of the building, and sometimes there would be this dead light coming from the edges. It’s like sometimes you see at sea ... little reflections of light, except it was greenish, that light.”

Federal authorities have acknowledged using a flamethrower carrying a thermobaric charge, a small, shoulder-fired version of the controversial fuel-air weapons wielded by the U.S. military against insurgents lodged in caves and bunkers in Afghanistan.

These weapons do not ordinarily cause fires, but they are described by Defensetech.org, a private information resource associated with the U.S. military, as “just about the most vicious weapon you can imagine -- igniting the air, sucking the oxygen out of an enclosed area and creating a massive pressure wave crushing anything unfortunate enough to have lived through the conflagration.”

Thermobaric flamethrowers immediately combust the oxygen in a room and ignite a 1,470-degree flash that chars everything in its path and creates a vacuum-induced blast wave that ruptures lungs and eardrums, causes hemorrhages in livers and spleens and yanks out the eyes of anyone caught within a 2,800-square-foot range.

Authorities say no heavy weapons were fired until all the hostages were dead. Flamethrowers, they say, were fired no earlier than 6 p.m. on Sept. 3, and the tank did not fire on the school cafeteria until after 9 p.m.

The public’s apparent unwillingness to accept these assertions without question is not without precedent: Doubts also emerged in 2002, when a botched government assault during a hostage crisis at Moscow’s Dubrovka Theater led to 129 deaths.

“Despite the unique cruelty of this case, there is unfortunately certain historical experience, and unfortunately, I believe it may have been repeated,” said Taimuraz Mamsurov, North Ossetia’s president. His two children, who were hostages at the school, were wounded. “This experience concerns the idea that the authorities, without a doubt, carry some of the blame.”

The military prosecutor’s confidential analysis, completed a few months after the siege, depicts a state of confusion and disarray among police and army units at the scene. Although some army commanders reported successfully ordering their troops not to fire, they also spoke of a barrage directed at the school from Russian Interior Ministry units, civilian militiamen and armored vehicles equipped with heavy machine guns, apparently acting on orders from the Federal Security Service, or FSB, the main successor agency to the KGB.

FSB units, the report said, were in “secret positions” that were apparently unknown to military units. Those units, the Interior Ministry troops and armed civilians were each “acting on their own, and not cooperating,” according to the report.

The clash began about 1:10 p.m. on the third day of the hostage crisis. An Emergency Situations Ministry vehicle, under an agreement with the militants, had just pulled up outside the school to begin loading the bodies of hostages who were shot on the first day and left outside.

“I heard a heavy explosion in the school building. After that, intense shooting started from the school. Fire was opened from the vegetable gardens [behind a private house near the school]. It’s unclear which divisions were shooting,” Senior Sgt. V.V. Utlov, commander of the army’s 2nd Division reconnaissance team, told military investigators.

Authorities now believe that one of the hostage-takers simply took his foot off the trigger of a bomb, said Shepel, the deputy prosecutor general. He said authorities were “leaning toward the theory” that the man, like many of the militants whose blood was later submitted for tests by investigators, was suffering from narcotics withdrawal.

But the sole surviving militant, Nur-Pashi Kulayev, testified at his trial in nearby Vladikavkaz that a sniper’s bullet had struck the triggerman.

The leader of the militants, he said, was on the phone with one of the negotiators. “He was like, ‘What have you done? Do you want to storm the school? Don’t you know how many people are here, children, women?’ Then he cut off the phone and told us to defend ourselves and shoot to the very end. ‘They will have no mercy for anyone here, anyway.’ ”

Zarina Tokayeva, a former hostage, remembered the same conversation. “You could see [the hostage takers’] faces were frightened, that they didn’t expect this explosion,” she said in an interview. “And that phrase, I’ll never forget it. ‘Your own people blew you up.’ One of the hostage-takers repeated this several times in this very deep voice. I’ll never forget it.”

Shepel rejects this scenario. “We checked this version that there was shooting coming from outside and that a sniper could have picked off the terrorist who was minding the button,” he said. “But as of today, there’s no confirmation for this story. The school had opaque glass through which it would have been impossible to discern particular figures and pick them off.”

But Fatima Dudiyeva, a Beslan juvenile division police officer who was sent to the school to provide routine security on the morning of the hostage-taking, said she was sure the first shot came from outside the school -- it hit her in the hand.

“We’d been sitting for a long time, and I stretched. I raised my hand, and there was a gunshot, and I felt blood running on my hand,” Dudiyeva said.

“This was the sound I heard.” She struck a glass sharply with a fork. “As if a stone had been thrown through a window.” A short time later, perhaps five minutes, one of the bombs in the gym went off and then another, she said.

What happened next is crucial to understanding why so many hostages died and what caused their deaths.

The first two bombs blew a hole through part of the roof and ignited a small fire. Fire, as it turned out, was the big killer: Of 290 burned corpses found in the gym, many mutilated by the bombs, only about 100 could be confirmed to have burned posthumously. Presumably, some or all of the others died in the fire.

What set the ceiling of the gym aflame?

Shepel said his investigation had shown that the initial explosions sparked a blaze that spread across the roof over the next 40 minutes. In interviews with The Times, hostages said the initial fire was only a minor flare-up in a corner until at least 45 minutes after the first explosions, and then the flames spread only after several loud explosions were heard on the roof, part of the intense firefight that was unfolding.

Most witnesses talk of a third, even louder explosion about half an hour to 45 minutes after the first detonations, the cause of which has not been explained.

Hostages say a period of hellish fire ensued, and some describe a series of loud explosions above the gym’s ceiling before it collapsed.

“It wasn’t the fire of automatic weapons. It was repeated, like bombing. Like shelling. The ceiling was shaking very strongly, and bits of it were crumbling down,” Tokayeva said. “At that point there were many people still alive, definitely. Dozens, at least, maybe more.”

Kazbek Misikov, a former army explosives expert, was among the hostages who stumbled into the weight room adjacent to the gym, where he briefly lost consciousness from his wounds. When he came to, he and a former teacher began trying to disconnect some of the bombs still in the gym.

At that point, he said, “one of the terrorists was taking some of the people away to the assembly hall, for the very good reason that part of the ceiling was about to collapse and because tanks were shooting at the school, although living people were still inside.”

He believed it was tank fire, he said, “because the whole building was shaking, and these weren’t grenades, it was something much more serious than that. Of course from outside there was firing from all kinds of weapons. Semiautomatics, machine guns.... By that time, I was more afraid of our own people than the terrorists.”

The next crucial point in the investigation concerns the heavy weapons that were fired at other parts of the school, especially the cafeteria and the nearby corridor, where militants had rounded up several dozen hostages immediately after the explosions in the gym.

Although investigators insist the extremely powerful shells of the main battle tank weren’t fired at the area until after 9 p.m. -- long after any hostages could have been alive -- a number of hostages say they saw tanks firing between 2 and 4 p.m.

This may be explained by a passage in the military prosecutor’s report, which said armored vehicles fired at the school as early as 2 p.m. Those not versed in military matters could well have confused an armored vehicle with a tank.

“We were told that they were dummy shells that were being used, so as just to break through a hole in the wall, without making an explosion,” said Tebiev, whose wife was killed. “But the hostages themselves say the firing was so intense they couldn’t even poke their noses out. They tried to wave white kerchiefs, but the shooting wouldn’t stop.”

In his interrogation by military prosecutors, a senior army lieutenant whose name was given only as Makutin said members of the Alfa and Vympel special forces units ordered his armored personnel carrier to move close to the school building at 3 p.m. “The armored vehicle was taking orders from the special service officers and was shooting at the windows on the second floor,” Makutin reported. At 4 p.m., the vehicle was deployed to removed the lattices from windows on the second floor of the school, he said.

Prosecutor general spokesman Sergei Prokopov said authorities closely examined the cafeteria after the siege. “At all locations where tank rounds exploded, dead bodies of terrorists were found, but not a single body of a hostage,” he said.

But much later, Tebiev said, residents got their hands on the videotape shot by the Emergency Situations Ministry, which revealed the corpse of a child lying in one of the areas hit by tank rounds. “When we showed this video to a member of the parliamentary [investigative] commission,” Tebiev said, “he was ready to pull his hair out.”

No matter what ignited the terrible blaze, a bungled firefighting effort may have led to more deaths. Not only did firefighters hold back in the face of the gunfire, but they initially also didn’t have enough water.

According to the military prosecutor’s report, a mine-clearing crew called for a fire engine sometime after 2 p.m., about an hour after the first explosions. The first fire engine arrived at 2:45 but had only about 53 gallons of water on board, less than it takes to fill an average kiddie pool. Its hoses did not have the proper fittings to connect to nearby hydrants.

“Another fire engine arrived at 3:45 p.m. and started extinguishing the fire,” the report said.

The next morning, investigators were greeted with a scene of carnage and the smell of burnt flesh. The Emergency Situations Ministry’s video of the scene is horrific.

“There is a layer of hundreds of burned corpses of children, women and men, which cover about half the surface area of the gym,” said a report from the investigators that was obtained by The Times.

Three scorched corpses of militants also were found in the gym, one of them holding an unexploded grenade. The bodies of several men were piled beneath a bloodstained window on the second floor and in the ground-floor hallway. In the second-floor hallway lay a hostage-taker’s headless corpse. His neatly severed head, apparently removed by one of the commandos with a knife, rested nearby. The right ear of another hostage-taker was missing, and next to the body lay the corpse of a boy 12 to 14 years old.

Now it will be up to the panel commissioned by the prosecutor general’s office to make sense of these facts and determine whether law enforcement acted properly.

“All of the laws were followed, and all of the actions were aimed at rescuing the hostages and saving people’s lives and health,” the military prosecutor’s report concluded.

A U.S. law enforcement expert said the decision to involve army and Interior Ministry troops predetermined the conduct of the operation.

“Once you get the military involved, their objective is not to get the hostages out, but to kill. That’s why the U.S., and most Western countries, went to civilian policing,” said Edward Mamet, a retired New York City police captain and an expert on police procedures. “You need disciplined officers who are trained to use force at a minimum, and with the military, there’s no such thing as minimum force.”

But George T. Williams, a police trainer from Bellingham, Wash., who has studied the Beslan operation, said it would be a mistake to compare the siege to a civilian hostage situation in the U.S. The episode in Beslan was a battle in an increasingly international war, he said.

“These weren’t criminals. They were terrorists who are at war with Russia and who took over 1,000 children, women and men hostages. It was a military operation, and in a military operation, there are going to be collateral casualties to hostages and civilians.”

Williams said Russian authorities appeared to have determined that it was necessary to enter and seize control of the school as quickly as possible with the goal of saving anyone left alive.

“I’m glad I don’t have to make that decision, but if I have to kill 20 hostages to save 300, then that’s what I’ll do. I’ll make that decision, and it is a military decision,” he said. “In order to eliminate the possibility of these terrorists escaping or causing more damage, they used military weapons to take them out.”

Beslan’s mothers do not see their children as “collateral casualties.”

Dudiyeva of the mothers committee said the town was determined to find answers and to make sure that someone would be held accountable for what happened.

“Russia is a country where there have been so many terrorist attacks, with each one more frightening than the previous one,” she said. “President Putin must now reconsider his policies.

“Because if nothing changes after Beslan, then the country, I’m afraid, is descending into a bottomless pit.”

Times special correspondent Svetlana Meteleva contributed to this report.