Jan Jarboe Russell first learned about Crystal City in 1971 when she was an undergrad at the University of Texas at Austin. Russell, who grew up in rural Texas, was curious enough about the first Asian-American she had ever seen to ask him where he was from.

“How did you get to Texas?” she asked architecture professor Alan Taniguchi.

“My family was in camp here,” he said.

“Church camp?” she asked.

“Not exactly.”

Crystal City is a small town situated 120 miles southwest of San Antonio near the Mexican border. In the first half of the 20th century, it was the self-proclaimed “spinach capital of the world” and even had a fiberglass statue of the world’s most famous spinach eater, Popeye. Many of the migrant workers who picked the spinach lived at a 290-acre worker camp owned by the Farm Security Administration.

In 1942, the Immigration and Naturalization Service began transporting “dangerous enemy aliens”—immigrants from Japan, Germany and Italy whom the United States government considered to be a threat to national security—to the Crystal City Enemy Detention Facility. Crystal City was a prison camp. There was a 10-foot barbed-wire fence around it, and the penalty for escaping was death.

There were other internment camps, but Crystal City was the only family camp. Alan Taniguchi grew up there. His father, Isamu Taniguchi, was a Japanese immigrant who had an apricot and almond farm in California that he lost when the FBI arrested him in 1942 for charges that were never clear because he was never given an indictment or a trial. The Taniguchi family lived at Crystal City for the duration of World War II and stayed in the area when it ended. Years later, Isamu Taniguchi built a Japanese garden near downtown Austin that is dedicated to peace and is still there.

Russell, who is a writer at large for Texas Monthly and author of Lady Bird: A Biography of Mrs. Johnson, went by Alan Taniguchi’s office several years ago for a surprise visit and learned that he had died. She met Taniguchi’s son Evan and began talking to him about Crystal City.

“Evan gave me a list of all of Alan’s friends from the Crystal City camp,” Russell says, “so I went home that night and started calling those people who were children in camp—Japanese-Americans and German-Americans who are now in their 70s and 80s. I started calling them, they started telling me about the camp, so I started getting on airplanes. That’s how this book evolved.”

The book, The Train to Crystal City: FDR’s Secret Prisoner Exchange Program and America’s Only Family Internment Camp During World War II, is Russell’s long-awaited answer to her question to Alan Taniguchi about how he came to Texas and a recounting of the shocking American policy during World War II of rounding up, detaining and imprisoning thousands of Japanese-American and German-American immigrants—many for little more reason that their country of origin.

“The head of the Nazi Party in America was interned in Crystal City, and he was certainly dangerous, but most of the people there were not,” Russell says. “The truth of the matter is that these people were the leaders of their communities. If you were a German engineer—like one of my main characters—then you were automatically suspected because if you could build a bridge, you could blow it up.”

The Train to Crystal City tells the story of the Crystal City camp through two particular families—one Japanese-American and one German-American—within the broader context of World War II and the Roosevelt administration’s internment policy. The U.S. government’s declaration of authority over the enemy aliens that were sent to Crystal City was modeled on the Enemy Alien Act of 1798, which essentially says that anyone who was born in or was a citizen of a country we are at war with can be interned because we are at war with their country. The fear was that they were loyal to Germany and Japan and could do us harm.

“I had no idea when I started that we interned German immigrants and their American-born children,” Russell says. “I had no idea that we interned thousands of people from Latin America. I first listened to the stories of the people who are now the characters in my book. Then I went to the National Archives and spent about a month researching documents about the camps.”

Russell also reports on the role of internment camps—and Crystal City in particular—in America’s policy of exchanging prisoners during the war.

“There was a division that created a pool of people who could be changed in prisoner exchanges,” she says. “Crystal City became a center for prisoner exchanges. Fathers would come to Crystal City and voluntarily agree to be exchanged so that they could get their families back together again. When the fathers were arrested, they lost everything—homes and farms and businesses.”

Scott Porch is an attorney and contributes to Kirkus Reviews and The Daily Beast. He is writing a book about social upheaval in the 1960s and '70s.