A man walks past Peter's Coffee House, owned by Canadian couple Kevin and Julia Garratt, in Dandong, China, on Tuesday. China is investigating the Garratts on suspicion of espionage. (STR/AFP/Getty Images)

— A Canadian couple who ran a coffee shop along China’s border with North Korea are under investigation on suspicion of stealing Chinese military and intelligence secrets and endangering national security, authorities said Tuesday.

Kevin and Julia Garratt opened Peter’s Coffee House in the Chinese city of Dandong in 2008, on the banks of the Yalu River just a few minutes’ walk from the Sino-Korean Friendship Bridge, the main crossing point between the countries.

In addition to offering coffee and Western food, the couple ran English conversation classes for local residents and helped tourists organize trips to North Korea, according to their Web site. They also, in Kevin Garratt’s words, tried to help the impoverished state next door “with God, with Jesus and with practical assistance.”

But Tuesday, calls to their coffee shop went unanswered, after the official Xinhua News Agency reported that they were under investigation. China’s Foreign Ministry said they were “suspected of collecting and stealing intelligence materials related to Chinese military targets and important Chinese national defense scientific research programs, and engaging in activities that endanger China’s national security.” In an e-mailed statement, it said that the couple were under investigation by the local branch of the National Security Bureau and that “their various rights have been fully guaranteed.”

Canada’s Department of Foreign Affairs said it was aware of reports of the couple’s detention, was gathering information and was “ready to provide assistance as required,” news agencies reported.

Simeon Garratt, son of Canadian couple Kevin and Julia Garratt, who are under investigation in China, speaks to a Reuters journalist outside his residence in Vancouver, B.C., on Tuesday. (Ben Nelms/Reuters)

The theft of military secrets in China “for foreign organizations” is punishable by sentences ranging from 10 years in prison to the death penalty. But if no foreign group is involved, recommended sentences range from “below five years to above 10 years.”

The investigation came a week after Canada for the first time publicly accused China of cyberespionage, echoing charges made by the U.S. government against the People’s Liberation Army.

Canada said “a highly sophisticated Chinese state-sponsored actor” broke into the National Research Council, the government’s leading research body. Canada lodged a protest, but China’s Foreign Ministry responded by accusing Canada of making “irresponsible” accusations that lacked “credible evidence.”

The Garratts have been in China since 1984, working as teachers before opening the coffee house in Dandong. They named it after their son, Peter Garratt, who also lives in the city, according to another of their four children, Simeon Garratt.

Canada’s Globe and Mail newspaper cited several sources as saying that the establishment may have garnered unwanted attention from authorities because it was frequented by Christians at a time when China has been cracking down on religion and North Korea has sentenced or charged two Americans with trying to undermine the state by promoting Christianity.

On the Web site for the coffee shop, the establishment is described as “the perfect stop off while en route to or returning from the Hermit Kingdom.” Photographs show that the letter “t” in its name is written in the shape of a crucifix.

In a guest sermon to the Terra Nova Church in Surrey, British Columbia, in November, Kevin Garratt said: “We’re China-based, we’re North Korea-focused, but we’re Jesus-centered.”

This undated picture, provided to AFP by Simeon Garratt, shows his parents, Kevin and Dawn Garratt, cutting the ribbon in the opening ceremony of their coffee shop in Dandong, China. (Simeon Garratt/AFP/Getty Images)

In an audio file posted on the church’s Web site, Garratt said God had told him in a prayer meeting to start a coffee house in Dandong.

In an interview with the Dandong Daily, Garratt said he strolled along the Yalu every morning, breathing in the fresh air, sometimes watching locals swim, sometimes pausing to look across at North Korea. “It is so interesting,” he said. “In one place, you can absorb the culture of two countries.”

Simeon Garratt, the couple’s oldest son, now working in British Columbia, said that he spoke to his parents Monday night before they went for dinner but that he and his brother grew concerned after they did not send photos from the meal as promised and their phones were later switched off. In an interview by e-mail, he called the charges “crazy,” adding: “I can’t really understand how/why that came about, and I feel that it was started from an unreliable source.”

Simeon Garratt said his parents had visited North Korea several times and sent in goods such as grains and oil to help people in need. He also said that they were being detained at Dadong Public Security Bureau and that Peter had been called in for questioning, as well as to bring his parents items such as clothes and toiletries.

Foreigners in China are rarely charged with stealing state secrets. However, Friday, British corporate investigator Peter Humphrey and his American wife, Yu Yingzeng, are due to go on trial in Shanghai on suspicion of illegally obtaining private information, in a case linked to corruption charges leveled against British drugmaker GlaxoSmithKline.

North Korea last year sentenced Korean American missionary Kenneth Bae to 15 years in prison for allegedly trying to topple the government, and it recently charged another American, Jeffrey Fowle, with anti-state crimes after he allegedly left a Bible in a nightclub.

Gu Jinglu contributed to this report.