Two hours later, in a confusing sequence of events, a group of armed Khmer stormed the guest house and in the ensuing fracas Caldwell and at least one of the intruders were shot and killed. Two middle-ranking cadre eventually confessed to the crime at S-21, indirectly implicating Son Sen, but the facts of the case remain obscure. One unlikely explanation is that Pol Pot ordered Caldwell killed before the Scottish radical could condemn Cambodia’s revolution. Caldwell’s discussion with Pol Pot was friendly, and Caldwell remained convinced only hours before he died about the justice of the Cambodian cause. It is more likely, as Stephen Heder has suggested, that Caldwell was murdered by opponents of Pol Pot to embarrass the regime. A third possibility—that Caldwell was a casualty in a personal feud among low-ranking cadre—should also be considered.38

On December 24, Becker, Dudman, and the coffin containing Caldwell’s body left Phnom Penh, as scheduled, for Beijing. The following day, the Vietnamese launched a massive attack on Cambodia. Fourteen divisions—some 100,000 troops—were involved. The well-trained, heavily armed Vietnamese sliced into Cambodia at several points, isolating the units thrown against them. They were supported by helicopters, fixed-wing aircraft, and heavy artillery units. Cambodian troops fought courageously and sustained heavy losses but were outmaneuvered and outgunned. On December 29, Pol Pot greeted a Marxist-Leninist delegation from Canada. He told them in a three-hour interview that the Vietnamese faced “imminent defeat,” adding that the “Warsaw Pact” was involved in the war. By January 1, 1979, the sound of artillery fire was audible in Phnom Penh, rattling the windows of Sihanouk’s cottage. On January 2, Vietnamese commandos crossed the Mekong on rubber rafts in an attempt to kidnap the prince. They were mowed down by Cambodian troops, and Sihanouk was immediately evacuated to the northwest for three days. By then, Vietnamese forces controlled seven Cambodian provinces east of the Mekong.39

Sihanouk returned to Phnom Penh on January 5, the same day that Pol Pot issued a stirring statement calling for a “people’s protracted war [against] Soviet international expansionism and the Warsaw Pact.” Late that afternoon, Khieu Samphan visited the prince to say that Pol Pot had invited him to tea. When Sihanouk’s Mercedes pulled up to the Residence Supérieure, the prime minister came to the door to greet him with a “slight bow.” The two men were dressed in short-sleeved white shirts and dark trousers—the costume Saloth Sar had favored years before in Chamraon Vichea. On several occasions, Sihanouk described Pol Pot that evening as “charismatic” and a “perfect host.” The prince told Nayan Chanda later that “Pol Pot is very brutal, but it seems he did not hate me very much. He was really very charming.”40