Known for its healing hot springs, mud baths and luxurious hotel accommodations from the late 1800s to the 1930s, the Byron Hot Springs had a secret identity in the early 1940s.

A secret everyone knew about.

Known as Camp Tracy, the hotel was bought by the United States government in 1942 and transformed from a palace of pleasure into an interrogation center for Japanese and German prisoners of war (POWs).

The four-story brick hotel was wired extensively with microphones installed in faux ceilings. The real shocker, though: it was friendly interrogation. What makes for a loose tongue better than a massage, table tennis, beer and cigarettes? It was the perfect weapon for extracting information.

It's also what brought associate film producer KojiroYamada from New York last month to film a documentary for a public TV station in Japan called NHK Special 60.

Photo courtesy of Carol Jensen

The Byron Hot Springs Hotel was a work of art in its day. It featured a large room on the first floor for fine dining.

Photos by Richard Wisdom

The filmmakers move in close to capture details of the now-dilapidated hotel.

"NHK Special 60 is the most watched documentary film station in Japan," said Yamada. "We have over 10 million viewers. The director of the documentary is Kurasako Keiji."

When completed, Japanese viewers will see a film about 2,000 Japanese POWs who spent anywhere from a few days to a week at Camp Tracy, depending on how loose their tongues were.

It will also include photographs and documents they've been pulling from the National Archives in Washington, D.C. since the early 1990s - the beginning of the 50th anniversary of the WWII years.

Yamada, who was born and raised in Tokyo, said the documentary's mission is to raise public awareness in Japan. "This was the last war for the Japanese. We want the younger generation, including myself, to know more about World War II," he said.

"It's very important for the Japanese to know about the Byron Hot Springs, because it's symbolic of how the Japanese and Americans understand each other," he added.

Extracting information by wining and dining is not what most Americans imagine when they hear the word "interrogation."

Dave Fowler, managing partner of the current owners of the Byron Hot Springs and its 160 acres, East Bay Associates LLC, was pleased friendly methods were used at Camp Tracy. "It did surprise me. They pretty much spoiled the prisoners," said Fowler. "What you get from all the movies are people pulling fingernails off. Instead they're in hot tubs, drinking and partying."

Fowler, a huge history buff, winner of awards for his historical restorations throughout the Bay Area, had a pressing question for Yamada. "I asked the producer if he could please research if any of the Japanese prisoners had come back to that soil (Byron) and saw fertile ground to do agriculture work," said Fowler.

Fowler has his suspicions some did, since he knows a couple Japanese agriculturalists in the neighborhood. He's also working to restore the Byron Hot Springs to its original grandeur.

"We're hoping to get through the process this year with the county and once that's done, we'll start anytime - could be weeks or months instead of years," he said. "I'm more than ready."

Carol Jensen, local historian and author of "Byron Hot Springs, California - Images of America Series," was thrilled to watch the Japanese film crew and cameramen take ground and aerial shots of a historical landmark she's known since she was a kid.

"This is real television! It's all professional," said Jensen, who is also on the County Advisory Landmark Board. "They found Japanese who were POWs still living in Japan for their documentary."

The hotel, she believes, is what put the spotlight on Byron in the first place.

"Before the Byron Hot Springs, all of East County was dry, wheat farming. Other than that, it was nothing," said Jensen. "It's what put the whole area on the map, in a commercial sense."

She laughs when told how Camp Tracy was a big secret operation in its day. "It was called a big secret, but it never was. Everyone knew about it," she said.

Even more interesting, yet completely understandable to Jensen, was how the camp was used. "Japanese and Europeans love the spa life," she said. "It made complete sense for the selection of that property. The reason for the Byron Hot Springs was to bring them there and 'kill them with kindness' and basically soften them up."

She's happy the internment camp was not used to put people on the rack. "They were relaxed, happy and well-fed."

She recalls the condition of the hotel when she was 16 years old. "There were still microphones in the light fixtures in every room. The whole place was doubly wired, with wires going down into the basement where the transmitters could eavesdrop on every conversation," she said.

The ground level of the building (the main entrance was one floor up) was the recreational room, where detainees could play piano and billiards. The back end served hotel staff rooms.

Jensen has come across many people who refuse to believe the United States held POW camps. "They say 'we would never do that!' Well, we did. It's shocking, but guess what: we had them."

As Yamada walked through the grounds charcoaled from countless fires, past the severed palm trees and the windowless, graffiti-ridden hotel, he reflected on what it means to him.

"At first glance I was simply surprised at how much damage it has today," he said. "But I feel the story we're working on is also symbolic - with all the damage, it's not what it used to be, just like our relationship between us and the U.S. - it's not what it used to be."

Visit www.byronhotsprings.com for more information on the history of the hotel.