By Paul Watson and Mubashir Zaidi

Ten days after Pakistan tested its first atomic bomb in 1998, the wife of a major North Korean arms dealer was shot to death near the heavily guarded home here of the nuclear program's leader, Abdul Qadeer Khan.

Authorities hushed up the mysterious shooting of Kim Sa Nae, and it was more than a year before news broke that she was probably killed by North Koreans. After Khan's confession in early February that he secretly sold nuclear weapons technology to North Korea, Iran and Libya, Kim's death is taking on a new meaning as fresh details emerge.

Pakistan's government and military say that Khan and at least seven associates were motivated by greed and acted without official knowledge or approval. But details of Kim's death on June 7, 1998, and the way Pakistani authorities handled it, may hold clues to what officials actually knew about Khan's activities.

Khan has admitted shipping nuclear secrets from at least 1989 to 2002 on what sources said were Pakistani air force cargo planes. U.S. officials and many nuclear weapons experts suspect that Pakistan aided Pyongyang's nuclear program in exchange for help with Islamabad's missile program.

But Pakistani President Pervez Musharraf insists his country bought missiles separately from North Korea, and that it did not barter nuclear secrets and technology for them. Musharraf condemned Khan on Feb. 5 as a black market profiteer. He also praised him as a hero for developing Pakistan's nuclear program and pardoned him.

Khan is now under house arrest in Rawalpindi, a high-security garrison town on the edge of Islamabad, which is home to many senior military and government officials. Kim was shot at point-blank range, a few yards from Khan's house in the neighborhood known as E-7, a senior police officer said in an interview.

Kim previously has been described as the wife of a mid-ranking North Korean diplomat. But present and former staff members at Khan Research Laboratories, or KRL, the Pakistani scientist's weapons development facility about 20 miles southeast of Islamabad, say that was a cover story.

The officials, speaking on the condition of anonymity, said Kim was part of a 20-member delegation of North Korean engineers and scientists whom Khan had invited to witness Pakistan's first underground nuclear tests on May 28, 1998, and to learn how to enrich uranium for a North Korean bomb, the Pakistani officials said.

There has long been speculation that Kim was killed by her own government because she was suspected of spying for the United States or another Western power. Officials in both Pakistan and rival India, whose intelligence services closely monitor Pakistan's nuclear and missile programs, backed that version of events.

A Pakistani official said his country's intelligence agents suspected that the United States was using Kim as a mole inside the North Korean delegation, but that her actions were uncovered by Pakistani and North Korean agents.

An Indian official who is familiar with his government's assessment of the killing said bluntly: "She was in fact killed by the North Koreans on the grounds that she was in touch with certain Western diplomats."

A Pakistani intelligence source said Kim and the rest of the North Korean delegation was staying in a guest house in the compound of Khan's home when Kim was killed. Even after reports the next year revealed she was probably killed on purpose, few Pakistani officials would talk about it. They said a neighbor's cook accidentally killed the North Korean woman when he fired a shotgun borrowed from a guard. Another account at the time claimed that one of Khan's neighbors accidentally killed Kim when his gun fired as he was cleaning it in the garage.

A coroner was not allowed to carry out an autopsy on Kim's body, and authorities told local police not to open a file on her death.

Khan told The Times in a 1999 interview that Pakistani intelligence services told him that Kim's death was an accident. "You Americans always try to put the blame on us," he said.

Three days after she was shot, Kim's body was spirited out of Pakistan on a chartered Pakistani cargo plane, a source said. The plane, a U.S.-built C-130 military transport, was the same one that Khan recently told investigators he had used to ship plans and equipment for making a nuclear bomb, according to the official, who is familiar with Khan's signed 12-page confession.

The plane carried Kim's body back to North Korea along with P-1 and P-2 centrifuges, used to enrich uranium to weapons-grade material, according to the source.

The cargo also included drawings, sketches, technical data and depleted uranium hexafluoride gas, which is converted into weapons-grade material in centrifuges, the source said.

The Pakistani source said the aircraft was under the control of his country's air force. The Indian official said the charter flight was operated by Shaheen Air International, one of several large corporations run by Pakistan's military. The company began operating in 1993, and its current chairman is the air force chief of staff, Air Chief Marshal Kaleem Saadat. Six of its seven directors are retired air force officers.

Pakistan's foreign office spokesman, Masood Khan, declined to comment on Kim's death, or whether the current investigation into Khan and his associates had uncovered any new evidence.

Officially, Kim was married to Kang Thae Yun, who had the title of economic counselor at North Korea's embassy in Islamabad.

But the U.S. State Department has identified Kang as one of North Korea's chief arms dealers in the 1990s.

Kang worked for North Korea's state-run Changgwang Sinyong Corp., which the State Department accused of missile proliferation and imposed sanctions under U.S. law several times from 1996 to last year.

Kang was suspected of providing Pakistan with advanced missile technology in exchange for plans and equipment to build a nuclear bomb.

"Changgwang Sinyong Corp. is a North Korean missile marketing entity and has been sanctioned repeatedly in the past for its missile-related exporting behavior," State Department spokesman Philip Reeker said in April 2003.

It "transferred missile-related technology to [Khan's] KRL," Reeker added. "The United States made a determination to impose penalties on both Changgwang Sinyong Corp. and KRL as a result of this specific missile-related transfer."

Kang left Pakistan a month after Kim's death.

Musharraf became Pakistan's military chief of staff in 1998, four months after Kim was killed, and he seized power in a bloodless coup in December 1999.