Former US diplomat describes advising American student's family during North Korea detainment

— -- A former U.S. diplomat, who said he counseled Otto Warmbier’s family for over a year after he was detained in North Korea, said the conversation he had with the family after they learned Otto’s dire medical condition was one of the most emotional of his career.

“It was a very, very, very emotional exchange,” Evans Revere told ABC News' Bob Woodruff in an interview for ABC News' "20/20." “I’ve never had a conversation with anyone than [the] likes of the one I had with [Warmbier’s father] Fred Warmbier that day. I was in tears.”

Revere retired from the Foreign Service in 2007 after spending years as one of the U.S. State Department’s top Asia experts. He now works as a private consultant for American families, using his contacts in North Korea to try to bring home detained loved ones.

Revere said he started working with the Warmbier family “within a day or so” after their son was taken into custody.

“I gave them the same advice that I’d given to other families,” Revere said. “They needed to be careful about the things that they might say, that the North Koreans might take offense [and] that might cause the North Koreans to react very angrily and badly.”

Watch the full story on ABC News' "20/20" Friday, June 23, at 10 p.m. ET.

Warmbier, a University of Virginia student from Wyoming, Ohio, was 21 when he was detained in North Korea and held for nearly 17 months before he was medically evacuated and flown to Cincinnati on June 13. He was then rushed to the University of Cincinnati Medical Center, where doctors said Warmbier was suffering from “severe neurological injury” and had slipped into what they called a state of unresponsive wakefulness. North Korea claimed that he slipped into a coma after contracting botulism and taking a sleeping pill shortly after his sentencing.

Warmbier died on Monday. His family declined an autopsy and said in a statement that their son had “completed his journey home.”

He was arrested in January 2016 at the airport in Pyongyang for allegedly trying to steal a propaganda poster while he was visiting North Korea on a sightseeing tour organized by the Chinese-based company Young Pioneer Tours. North Korea regarded his alleged act as a “significant offense” against their sovereignty, Revere said.

After a one-hour trial in March 2016, Warmbier was convicted and sentenced to 15 years of hard labor.

Revere said it is difficult to know for sure whether Warmbier would have served the full 15 years. One of the first things Revere said he told the family was that their son would be released when the North Koreans were “done with him, when he is no longer of value to them, when they don’t see any utility to his continued incarceration.”

Sue Mi Terry, a senior research scholar at Columbia University who served as a senior analyst on North Korea for the CIA from 2001 to 2008, said the North Koreans can see American hostages as a “bargaining chip.”

“You can get a high-level visit from Washington, and that is a good propaganda coup domestically to say, ‘Look they came, they bowed before me, and I am a benevolent ruler getting and freeing these people,’" Terry said. “So you can always use American hostages as leverage.”

Terry made note of the fact that four days after Warmbier was arrested, on Jan. 6, 2016, the North Koreans conducted their fourth nuclear test.

“By the time they arrested Otto, they knew they were going to have a nuclear weapons test,” Terry said. “It takes weeks to prepare such a test. So they had in mind that they were going to do nuclear tests, and there’s going to be sanctions that follow.”

When the North Koreans began calling their American hostages “prisoners of war,” Revere realized the situation was changing.

“They kept using that word in a meeting with me,” Revere said. “I realized that what they were trying to tell me was that all bets were off in terms of the rules that they were required to follow in dealing with Americans.”

In April, the Warmbier family decided to break their silence. They gave an interview to Fox News host Tucker Carlson, in which they said the State Department had been “absolutely no” help in getting their son back and that when they met with then-Secretary of State John Kerry, they found him to be “totally exasperated and overwhelmed with North Korea.”

At a press conference last week, Warmbier’s father, Fred Warmbier, was asked if the Obama administration should have done more to help. “I think the results speak for themselves,” he replied, adding that they decided to speak out because they were frustrated by the situation.

The Warmbiers also met with former New Mexico Gov. Bill Richardson, who also served as U.S. ambassador to the United Nations, who said he made numerous efforts to bring their son home.

“My organization [The Richardson Center] worked with the family, briefed them, tried to get Otto out,” Richardson told ABC News. “I personally met with the North Koreans 20 times in the last year at the United Nations.”

The Warmbiers declined ABC News’ repeated requests for an interview.

Revere said he had heard this “sense of frustration and anger” from the Warmbier family during the time he was advising them.

“And I understand it,” he continued. “I sympathize with their feelings, even if I don’t necessarily agree with how they voice those frustrations.”

Revere never met or spoke with Otto Warmbier and was not directly involved with the negotiations for his release, which were handled between the State Department and the North Koreans.

He said the last conversation he had with the Warmbier family was shortly after they learned of their son’s condition, but he hopes he can continue to advise them in the future.

“I feel in a certain way I became part of their extended family,” he said. “I never met Otto Warmbier but I have tremendous respect for him and the life that he led as a young man.”

ABC News' Morgan Winsor contributed to this report.