Captured at 17

Mr. Tran calls himself Duke now, but his name at birth was Tran Duy Duc. He was born in Vietnam in 1961, the son of a colonel in the South Vietnamese military fighting alongside American troops. Mr. Tran was 13 when, in 1975, the North Vietnamese took over the government and sent his father to a prison camp as punishment for helping the Americans. When released four years later, Mr. Tran’s father paid to sneak Mr. Tran over the Cambodian border.

“You have to leave,” his father told him.

As soon as he got to Cambodia, though, Mr. Tran was captured by fighters for the genocidal Khmer Rouge regime. They forced him to drink vinegar, believing he had swallowed gold and family jewels that the vinegar would help expel. Then they made the 17-year-old their slave, forcing him to dig wells.

“Sometimes the soldiers got drunk and took me out and put AK-47s to my head so I would pass out,” Mr. Tran said.

Eight months after he was caught, Mr. Tran’s captors traded him to aid workers who carried humanitarian supplies. He still remembers the items that bought his freedom: a kilo of rice, two boxes of canned tuna, two boxes of sardines in tomato sauce, antibiotics and some other medical supplies.

The aid workers took him to Thailand. From there, the International Organization for Migration helped him reach the United States.

“I am so grateful,” Mr. Tran said. “Here I am, an American citizen.”

His first job in America was scrubbing pots in a restaurant kitchen. Soon after that, he got his first call center job, in the payment processing division of a local bank. He said in an interview that he had worked in call centers for a total of 25 years.

In 2002, he began working in a call center for Wells Fargo’s collections unit in Vancouver, Wash. In March 2013, he transferred to another Wells Fargo unit, the home equity division, in nearby Beaverton, Ore.