There’s a new clue why an 85-year-old American vet was detained by North Korea

The saga of the detained American war veteran in North Korea continues.

Merrill Newman, 85, has been held since late October, when he was taken off a plane by authorities just as he was wrapping up a visit to North Korea. A video of Newman, a Korean War vet, apologizing for his "espionage and subversive activities" was released over the weekend. The video has been described as likely coerced and little more than propaganda. 

In the video, though, he also admits to something he reportedly did do during the Korean War: advise the UN Korea 6th Partisan Regiment, a secret unit that supported North Korean partisans fighting behind enemy lines.

Col. Ben Malcom served as part of a similar unit during the war.

His memoir, "White Tigers: My Secret War in North Korea," is an account of his experiences leading partisans behind enemy lines in North Korea.

"I went into North Korea in January 1952 and was in North Korea for one year," he says. "I was the only American with 800 North Koreans."

The operation was classified top secret until the 1990s, Malcom says.

"In January 1951, the South Korean Navy had a patrol ship up near the Yellow River and they found over 10,000 North Koreans fighting behind the lines in pockets of resistance against the North Koreans," Malcom says.

The partisans, according to Malcom, requested military assistance, and a top secret United Nations partisan warfare mission was established to support the North Korean rebels. Malcom thinks Merrill Newman's past involvement with the secret operation was what got him into trouble.

Malcom says that Newman "had been to South Korea several times meeting with his 6th regiment of people … who had come out of North Korea and were still living in South Korea." When they heard that Newman was planning to visit North Korea, Malcom guesses that they asked Newman to check and see if their relatives were still alive there.

"And he started making contacts with his tour guide," speculates Malcom. "All of a sudden, North Korea started looking into his background. And I don't think they fully pulled all that together until he actually got onto the plane and they arrested him on the plane."

Malcom says he would never make a similar mistake. "No way I'd go back," says Malcom. "With my name, I wouldn't hardly get off the plane before I'd get arrested."