MOSCOW — "Nonsense," snaps retired Capt. Anatoly Safonov when asked about the official verdict that no one was to blame for the torpedo explosion that sank the Kursk nuclear submarine, killing its entire 118-man crew two summers ago.

Safonov, whose son Maxim died in the catastrophe, and relatives of many other seamen, call it a cover-up.

"They have never explained why the torpedo exploded," says Safonov, his voice trembling with anger. "The submarine sank, all its crew died, and now they tell us that no one was to blame."

The Kursk, one of Russia's largest and most advanced submarines, suffered two powerful explosions and sank during naval maneuvers in the Barents Sea on Aug. 12, 2000.

It was not just a tragedy but a national humiliation, compounded by bungled rescue efforts, that cast Vladimir Putin in a bad light just seven months into his presidency.

Still, compared with Soviet times, when such a disaster might have been kept a secret, the vigorous public debate that still rages is testimony to the country's post-communist openness.

Lt. Maxim Safonov, who was the Kursk's navigator, turned 26 just four days before the disaster and was going to marry soon. He died in a huge fireball that swept through the hull and pulverized most of the crew who had gathered in the control room.

The bodies were recovered when the wreck was raised last October from 356 feet of water. Prosecutors have scoured the gutted hulk for clues but say the ship's log and audio tapes showed nothing awry until the blast.

Prosecutor General Vladimir Ustinov closed the books on the catastrophe last month, backing up a government commission's supposition that a leaky torpedo was the only possible cause.

"The investigators have decided to close the criminal case since no evidence of a crime has been found," he said.

He said the initial blast was triggered by highly volatile hydrogen peroxide in the torpedo's propellant seeping through tiny cracks and exploding upon contact with kerosene and metal. Weapons then blew up in the bow in a blast equivalent to a mild earthquake.

"Those who designed the torpedo couldn't foresee the possibility of its explosion," Ustinov said.

But the torpedo's designers insist they had developed safeguards against such accidents.

"In the best case, the real truth about what happened on the Kursk may pop up in some 25 years," said Svetlana Baigarina, the widow of crewman Murat Baigarin. "Now the officials will say whatever is convenient for them."

Some relatives say the seamen had talked about a torpedo flaw before setting out to sea. Nadezhda Tylik, mother of Lt. Sergei Tylik, who died in the control room, said people at the submarine base told her after the disaster that the torpedo had been accidentally dropped before being loaded aboard.

"The crew knew what it meant," said Tylik, recalling her son telling her before the last mission that the Kursk was carrying "death on board."

Prosecutor Ustinov insisted no evidence was found that the torpedo had suffered any damage or malfunction.

Tylik accused the prosecutors of covering up the accidental dropping of the torpedo. "They want to protect the navy's top brass," she said in a telephone interview from her home in the southern city of Anapa. "The evidence is buried somewhere in their files, and they will never tell us the truth."

Tylik is preparing to sue the military for damages. Other relatives have hired a lawyer to help them weigh legal action.

Prosecutors have promised that relatives will have access to the 133-volume case file, but they haven't said when.

Safonov, the retired navy captain, said post-Soviet degradation of the navy was a key factor in the disaster.

During Soviet times, giant submarines were built to destroy U.S. aircraft carriers with cruise missiles and nuclear-tipped torpedoes. But since the 1991 Soviet collapse, most nuclear submarines and other navy ships have languished dockside for years for lack of funds.

When production stopped at defense plants in the Soviet republics after they went independent in 1991, it became hard to find replacements.

Retired Capt. Igor Kurdin, the head of St. Petersburg's Submariners' Club, said he had found out that the torpedo that exploded was manufactured in Kazakhstan during the political chaos of the months before the Soviet collapse.

Four out of 10 torpedoes of the same lot were discarded in the past decade because of micro-cracks in the welding seams, Kurdin told The Associated Press. The Kursk's torpedo successfully passed all checks, but the cracks could have gone unnoticed and grown bigger later, Kurdin said.