Merrill Newman is 85 and suffers from a heart ailment. But that did not deter him from fulfilling his wish to return to North Korea where he fought as a young man.
With a companion from his California retirement village, Newman booked a nine-day trip to the most closed society in the world. But he was detained there nearly a month ago and his whereabouts remain unclear.
"Why do second world war veterans go back to Normandy?" asked Newman's son Jeff, adding: "The war had a powerful impact on him."
Newman and his friend had ended their tour and were on a Koryo Airline plane on the tarmac in Pyongyang ready to leave for Beijing on October 26 when North Korean officers escorted him off, his son said. He has not been heard from since.
The day before they were scheduled to leave, Newman had a conversation about the Korean War and his service as a soldier with one of his tour guides and another Korean whose identity is not known, his son said.
Newman was upset afterwards and indicated to his friend, Bob Hamrdla, that the talk did not go well, his son said.
Newman was part of a small but growing number of Americans, Europeans and Chinese who have signed up in recent years to visit the North on state-sanctioned tours, despite it being a police state that tightly controls access to its people.
Jenny Town, assistant director of the US-Korea Institute at Johns Hopkins School of Advanced International Studies, said: "Tourism is on the rise, especially of Americans, because it's such an isolated state. People are kind of fascinated by the novelty of going somewhere where no one else has gone."
Tourists must be accompanied at all times by state-authorised guides who prevent much interaction with ordinary people. Itineraries are set in advance.
"It tends to be for curiosity seekers who have been everywhere and want to see the place," said Tony Namkung, a North Korea expert.
Newman travelled to North Korea with Juche Travel Services, an agency that advertises offices in Beijing, London and Berlin.
A person familiar with the situation surrounding Newman's disappearance said that inquiries by the Swedish officials in Pyongyang who represent US interests there had been "stonewalled".