Twenty-three years after his black-pajama-clad guerrillas marched into Cambodia's capital and launched one of this century's most horrific genocides, Khmer Rouge leader Pol Pot died quietly Wednesday on a flowered mattress in a wooden-slatted hut.

Televised footage from the Khmer Rouge's jungle haven tonight showed Pol Pot's lifeless body, arms at the sides, stretched out on a simple wooden bed, a green blanket partially covering his legs and his plastic sandals at the bedside. The former dictator's body lay where his wife discovered it when she went to arrange his mosquito netting.

American journalist Nate Thayer, a correspondent for the Hong Kong-based Far Eastern Economic Review, returned to Thailand from the Cambodian jungle tonight and said he had no doubt the body was that of Pol Pot. "He's dead," Thayer said in a telephone interview. "That was Pol Pot. There was no question that was Pol Pot."

Thayer said he spent several hours questioning Pol Pot's wife and daughter, as well as Ta Mok, the Khmer Rouge commander who replaced Pol Pot as head of the outlawed guerrilla group, and said he believed the Khmer Rouge reports that Pol Pot, 73, died of natural causes. Thayer also said he inspected the body, poking it several times, and saw no outward evidence of foul play.

"He'd been fleeing for the last 20 days under very difficult circumstances," Thayer said. "It would be very logical that he would succumb, because he was a very sick man to begin with."

In the last known film of him, taken last July, a white-haired Pol Pot appeared frail and sickly, suffering from malaria and unable to walk without assistance.

Thai officials in Bangkok -- who had kept a close watch on Khmer Rouge movements just across the Cambodian border -- had been cautious in assessing reports of the demise of the dictator deemed responsible for the deaths of between 1.5 million and 1.7 million Cambodians in the late 1970s. "We are still awaiting independent verification, but everything points to it being true -- that Pol Pot is dead," said Kobsak Chutikul, the Thai Foreign Ministry spokesman.

Officials in Bangkok sent a military team to verify the death reports, and they took a handful of Thai journalists whose television footage has now been broadcast worldwide.

In Phnom Penh, the Cambodian capital, which was celebrating the end of the lunar new year holiday, officials demanded to see Pol Pot's body before accepting the truth of his death. Local Cambodian radio and television carried no reports about Pol Pot's death, and those Cambodians informed of it by journalists seeking comment were mostly skeptical, saying they had heard such reports too many times before.

Fueling the skepticism was the extraordinary coincidence of Pol Pot's passing, which came as the Clinton administration was gaining international support to put him on trial and as the remaining Khmer Rouge guerrillas seemed ready to turn over their longtime leader.

"I don't want to believe that he's dead, and I don't have time in my life to believe Khmer Rouge propaganda anymore," said Youk Chhang, director of the Documentation Center of Cambodia, which has been compiling genocide evidence for use at a tribunal.

"If he's dead, hand over his body to the people, don't just take photographs," said Youk Chhang, interviewed by telephone in Phnom Penh. "I want to see him handcuffed and pushed into a jail, like his cadres did to me 20 years ago."

Youk Chhang expressed the frustration of many people -- Cambodians, scholars and human rights advocates who had hoped for an international war crimes trial -- that Pol Pot's death has robbed the world of the chance to force him to answer for his crimes and, in the process, to try to decipher the roots of his evil.

"Those who survived and suffered through his genocide are never really going to have closure," said American journalist Sidney Schanberg, whose Cambodia memoir served as the basis for the movie "The Killing Fields."

But President Clinton said in a White House statement that Pol Pot's death should not end efforts to bring to justice other Khmer Rouge leaders who share responsibility "for the monstrous human rights abuses committed during this period." And equally, the statement said, "we must renew our determination to prevent such atrocities from occurring in the future."

Thayer, who has spent a decade tracking the elusive Khmer Rouge leader and who last year became the first journalist to interview him in 18 years, said: "A lot of questions died with him. Obviously, justice wasn't served and now . . . can't be."

Youk Chhang said Pol Pot's death "is not the end of the genocide history of Cambodia" because "he alone could not kill 1.6 million Cambodians." Some top-ranking Khmer Rouge leaders who assisted him, such as Ieng Sary, have defected from the movement and are now living freely in Cambodia. The notorious one-legged commander Ta Mok, known as the Butcher, now leads the Khmer Rouge, believed to number just a few hundred guerrillas.

While Pol Pot's death may have cheated his victims of justice, his demise, without an international trial, also avoids the troubling and embarrassing questions a public airing of his crimes would have raised.

Hun Sen, the current Cambodian strongman, was a Khmer Rouge member who defected only after he was targeted for execution. King Norodom Sihanouk, who lost several relatives in Pol Pot's bloody purges, agreed to serve as the nominal leader of the Khmer Rouge-led resistance coalition fighting Vietnamese occupation for more than a decade beginning in 1978.

The United States, through three administrations, provided covert aid to that three-party coalition -- even though Pol Pot's Khmer Rouge was by far its dominant member. And when Pol Pot's guerrillas were isolated and near extinction on the Thai-Cambodian border, China supplied them with massive amounts of money and arms.

But Pol Pot's death changes nothing in Cambodia's current political landscape. Cambodians are preparing for elections in three months that will pit Hun Sen against the royalist rival he ousted last July, a vote Hun Sen hopes will afford him international legitimacy. While the country's dominant political factions were feuding, the aging Pol Pot had ceased to be a major factor; he was denounced by his followers in a show trial and held under house arrest in the remote jungles of Anlong Veng, near the Thai border. The once unified Khmer Rouge recently had been rocked by defections, starting in August 1996, when Ieng Sary -- Pol Pot's "foreign minister" and known as "Brother Number Two" -- defected to Hun Sen's camp, taking several thousand loyalists with him and being allowed, in return, to remain in control of his longtime base in western Cambodia.

Ieng Sary's switch prompted Hun Sen and Prince Norodom Ranariddh -- Hun Sen's co-premier and chief political rival, as well as Sihanouk's son -- to begin scrambling for support among other disaffected Khmer Rouge units. Ranariddh's contacts with Pol Pot's forces at Anlong Veng prompted Hun Sen to stage the violent coup last summer that ousted the prince and left Hun Sen in sole power.

Disputes among Khmer Rouge elements over whether to bargain with the government leaders led to a bloody split among the guerrillas, prompting Pol Pot to order the execution of Khmer Rouge defense minister Son Sen and his family -- an act of bloodletting that led Ta Mok to depose and arrest Pol Pot.

Two weeks ago, a mutiny by several thousand Khmer Rouge guerrillas at Anlong Veng reduced the number of Ta Mok's diehards to about 1,000 and sent many fleeing to new strongholds in the jungle. Among them was the captive Pol Pot, whose death was reported on the eve of the April 17, 1975, anniversary of the Khmer Rouge takeover of Phnom Penh. CAPTION: A television photographer takes a picture of Pol Pot's body, stretched out on a simple bed in a hut in Anlong Veng, Cambodia. The former Khmer Rouge dictator's body lay where his wife said she discovered it late Wednesday.