Newman's role as a "White Tiger" was to train anti-communist guerillas fighting behind enemy lines.
An undated photo shows Newman posing with some members of that guerilla unit in South Korea, decades after the Korean War.
Newman reportedly visited South Korea twice over the past ten years.
In his videotaped apology released by North Korean state media Friday night, the Palo Alto resident accepts responsibility for helping anti-communist guerillas.
The guerilla unit was called the "Kuwol Regiment," named after a North Korean mountain where the guerillas sought refuge.
Many are now questioning why Newman went to North Korea, given his role during the Korean War.
One fellow White Tiger, retired U.S. Army Colonel Ben Malcom, believes Newman went to do a favor for his former guerillas.
"I think some of those people may have indicated they may have relatives still living in North Korea," he said. "And they probably asked him, would he try to find those and maybe talk to those people and let them know what the conditions of those families were. So as a result of that, that led to him seeking some of those people in North Korea and led to those people picking him off the plane and detaining him at the present time."
Thomas Henriksen, a senior fellow at the Hoover Institution, wrote about North Korea in his book, "America and the Rogue States."
He's not sure if Newman will be released, especially if the regime considers him a war criminal, but he does think Newman is being used.
"There's a real possibility that the confession will be used, this phony confession will be used to extract something from the United States," Henriksen said.
Like in 2009, when Kim Jong-il demanded a meeting with President Bill Clinton before releasing two American journalists.
In Newman's hometown of Palo Alto, residents have tied yellow ribbons outside the retirement facility where he and his wife live. The release of the video has shaken many of those in Palo Alto.
"I saw the video, I just think it's terrible," Palo Alto resident Megan Mozart said. "I think it's awful, poor guy, I feel bad for him."
Newman's family wouldn't comment on the video, but did say Saturday that the Swedish ambassador told them "Merrill reports that he is being well treated and that the food is good."
The U.S. State Department has reviewed the North Korean state media report and the video.
In a statement, the department urged Pyongyang to release the 85-year-old American, saying, "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."
The 85-year-old has been detained now for nearly five weeks.
The U.S. State Department is also advising US citizens against travelling to North Korea.
