American tourist Jeffrey Fowle was arrested by North Korean authorities for leaving a Bible under a bin in the toilet at a club for foreign sailors, a source familiar with Fowle’s case said.

During his 10-day trip to North Korea, Fowle’s fellow travelers described the middle-aged street repairs worker from Miamisburg, Ohio, as a warm, amiable, quiet man.

On May 4, toward the end of an evening spent eating and drinking in Chongjin, a large industrial city on North Korea’s east coast, Fowle’s action led to him being thrown in jail, where he is awaiting trial in one of the world’s most inhospitable countries.

He left a bilingual English-Korean Bible in the restaurant he and his fellow travelers were about to leave, said the source, who wished to remain anonymous because of the sensitivities surrounding the case.

In it, Fowle had written his name and phone number, and inserted photos of himself and his family between its pages.

He was arrested three days later at the airport where he was due to board a flight out of North Korea.

Fowle and fellow detained U.S. tourist Matthew Miller — who was arrested in April for a separate incident — said they will face trial soon and have called on the U.S. government to help secure their release in an interview to the Associated Press, released Friday.

A handwritten letter from Fowle shown in the interview confirmed he was arrested for intentionally leaving a Bible in the northern city of Chongjin.

It is unclear why Fowle left the Bible, the source familiar with Fowle’s case said. Media reports in Ohio said the 56-year-old is a churchgoer and was once a member of his school’s Bible club — but there is little evidence to suggest he was a missionary.

The source familiar with Fowle’s arrest also said he did not seem overtly religious.

Yet, at the Chongjin Seamen’s Club — a faded compound originally designed as a hostel for visiting mariners that sells foreign whiskeys and serves local food — Fowle wrapped a bilingual English-Korean Bible bound in fake leather in a Chinese newspaper and hid it in the restroom, under a bin designed to discard the used toilet paper North Korea’s aging plumbing can’t handle.

A cleaner found the package, and alerted local authorities.

When his guides asked if anyone had left anything at the club — a small cluster with shops, a sauna and noodle restaurants also open to locals with the cash to spend on cheap drinks — he said it was him, and that he “must’ve dropped it.”

Fowle said at the time the Bible had “fallen out of his pocket” when using the squat toilet, but the Bible was too big to be pocket-size, the source said.

While North Korea technically espouses freedom of religion it is ranked as one of the world’s most oppressive regimes in terms of such freedom. Pyongyang has dismissed recent reports on its oppression of religion as an attempt by the United States to “tarnish the image” of the isolated country.

Two months before Fowle visited North Korea, Australian missionary John Short had been arrested for leaving Bible tracts at areas open to tourists in the isolated country. Short, 75, was released on account of his advanced age after state media released a written apology.

Fowle appeared in an Associated Press video on Friday alongside Miller, who was arrested for ripping up his tourist visa and attempting to claim political asylum, according to state media.

North Korea has three U.S. citizens in custody, including Kenneth Bae, a missionary of Korean descent who was arrested in November 2012 and convicted and sentenced to 15 years hard labor last year.

Chongjin is one of the most sensitive cities open to tourists visiting North Korea. The scene for much of journalist Barbara Demmick’s “Nothing to Envy” book, based on a collection of interviews, it is the very epitome of the grim, gray Orwellian North Korea recalled by defectors.

“They don’t mess about in Chongjin,” one tourism source with experience of working in the city said.

If Fowle had hidden a Bible anywhere else in North Korea, he probably wouldn’t have been arrested, sources in the North Korean tourist industry said. Sources working in North Korea are often forced to remain anonymous when talking to the press for fear of state reprisal or loss of business.

If the staff at the Seamen’s Club who found the Bible had told Fowle’s guides, and not the authorities, they might have avoided the arrest too, the source familiar with his arrest said.

Fowle hid the Bible on May 4. He later admitted to the group that he had left it there deliberately, for “someone to read.”

The rest of Fowle’s group didn’t talk to him when they heard what he had done. They felt he had put them in danger.

After the incident, Fowle had two days of normal sightseeing in Pyongyang, where he took photos of large bronze statues of North Korea’s former leaders, Kim Il Sung and Kim Jong Il.

He was arrested on May 7, once he cleared customs at Pyongyang’s Sunan Airport.