The bizarre and baffling tale of an elderly Palo Alto man who’s been detained by North Korea for more than a month grew even more mysterious Saturday as new details emerged about his role during the Korean War secretly training anti-communist guerrillas fighting behind enemy lines.

New revelations that 85-year-old Merrill Edward Newman had served in a once-top-secret U.S. Army unit nicknamed the “White Tigers” explains why the North Koreans detained the retired corporate finance executive last month as Newman was about to leave with a fellow Palo Alto traveler after a 10-day visit.

Since the North Koreans believe that the war with South Korea and the United States technically never ended because no peace treaty was ever signed, Newman is now essentially a “prisoner of war” in a conflict that took place six decades ago.

Many of the revelations also shed light on the videotaped “apology” that Newman gave his captors Nov. 9, when he purportedly admitted committing crimes during the war as well as “hostile acts” against the state during last month’s visit. Many details are contained in a lengthy new Reuters News report and U.S. Army documents that were unclassified in the early 1990s.

In the rambling “confession,” which the North Koreans released Friday, Newman ostensibly accepts responsibility for helping a guerrilla group called the Kuwol Partisan Regiment — which was under the command of the U.S. Army’s 8240th Unit — attack and kill North Korean soldiers as civil war was raging throughout the peninsula. But he does not mention the group by name.

“As I killed so many civilians and KPA (Korean People’s Army) soldiers and destroyed strategic objects in the DPRK (Democratic People’s Republic of Korea) during the Korean War,” Newman said in the video, reading aloud from a handwritten statement, “I committed indelible offensive acts against the DPRK government and Korean people.”

In the video, Newman seems at ease as he reads aloud from a handwritten statement in a wood-paneled room. At the end, he bows and places a fingerprint on the document.

“I realize that I cannot be forgiven for my offensives (offenses) but I beg for pardon on my knees by apologizing for my offensives (offenses) sincerely toward the DPRK government and the Korean people, and I want not punish me,” Newman, who has heart problems, was quoted as saying in often ungrammatical and stilted English by the North’s KCNA news agency. It characterized him as a mastermind of clandestine operations and accused him of killing civilians during the war.

According to a lengthy report from Reuters Saturday, the Kuwol Regiment, or “Kuwolsan” in Korean, meaning “September Mountain,” was named after a mountain in western North Korea where the guerrillas sought refuge as soldiers of the KPA swept down the Korean peninsula when war broke out.

From there, the guerrillas fought their way to North Korea’s west coast and sailed to offshore islands where they launched last-ditch battles against the North Korean army. Newman, according to several former fighters interviewed by Reuters, was their adviser. They said the North Koreans have probably known about him for years.

“Those bastards already knew Newman before the war was over,” Kim Chang-sun, who was still at school in 1953 when he joined the guerrilla regiment that Newman helped train, told Reuters. “They obtained the roster of our entire regiment.”

The new information about Newman’s wartime record raises a big question: Why would the Palo Alto grandfather undertake such a risky trip to North Korea, assuming authorities there knew all about Newman’s past?

Newman had already made two trips to South Korea during the last decade, according to Reuters, which published photos of Newman posing with the former guerrillas both in South Korea and in Palo Alto.

“In the eyes of the North Koreans, he would have literally been a spy engaging in some kind of espionage activity … I wouldn’t go there (if I were him),” Kim Hyeon, now 86, told Reuters. He has kept in touch with Newman and even visited him in Palo Alto in 2004.

Even more intriguing in the video was Newman’s alleged admission during this most recent trip that he “had a plan to meet any surviving soldiers and pray for the souls of the dead soldiers. Following the itinerary I asked my guide to help me look for the surviving soldiers and their families and descendants because it was too hard for me to do myself.”

For Newman, “the Korean War ended 60 years ago, and it looks to me like he was trying to get some closure on that experience,” said Dan Sneider, a North Korea expert at Stanford’s Shorenstein Asia-Pacific Research Center. “But for the North Koreans, the war is not over, and in many ways they’re still fighting it. And it seems that Mr. Newman inadvertently walked into an historical minefield that he wasn’t fully aware of.

“I hope the North Koreans are about to release him,” Sneider said. “But we’ll find out soon enough.”

The White House and the State Department on Saturday urged North Korea to set Newman free, particularly in light of his age and heart problems.

A State Department official who requested anonymity told this newspaper that while American authorities had seen the report on Newman’s alleged confession, the U.S. government was unsure about why the North Koreans were still holding him.

“According to the report,” the statement said, “Mr. Newman apologized for the misunderstanding that led to his detention. We have no other information regarding the reason for his detention. Given Mr. Newman’s advanced age and health conditions, we urge the DPRK to release Mr. Newman so he may return home and reunite with his family.”

Members of Newman’s family released a statement Saturday that did not address the new videotape or subsequent revelations. But the statement said that the State Department had told the family that the Swedish ambassador to North Korea had visited Newman on Saturday at a Pyongyang hotel and found him to be in good health.

“He has received the medications that we sent him and medical personnel are checking on his health several times a day,” the statement said. “Merrill reports that he is being well treated and that the food is good.”

The Kuwolsan soldiers are depicted in popular culture in South Korea as heroes in the fight against communism. The regiment and its guerrillas were the subject of a 1965 film called “Blood-soaked Mt. Kuwol.”

Kim Chang-sun, the former guerrilla, recalled Newman as a big American military officer with a warm heart who supervised their training and landing operations. “He had this U.S. Army food box and shared that with us,” said Kim, now 81. “He stayed with us at a bunker.”

While Newman’s motives for traveling to North Korea remain elusive, his own words raise the possibility that he was somehow trying to make amends with his own past or attempting to help the families of the men he had grown so close to while training them to kill.

“Kuwolsan was among the most effective guerrilla warfare units,” Newman wrote in a message attached to a book published by the Kuwolsan Guerrilla Unit Comrade Association in Seoul. “I am proud to have served with you.”

Staff writers Howard Mintz, Josh Richman and Kristin J. Bender contributed to this report.