Matthew Miller, the U.S. citizen imprisoned in North Korea on espionage charges, spent months in South Korea pretending to be an Englishman named “Preston Somerset,” acquaintances who met or worked with him say.

The 25-year-old native of Bakersfield, California, did not seem to have close friends, a regular job or means of support during the months he spent in Seoul over a period of at least two years, they said. He gave no inkling of any interest in nuclear-capable and unpredictable North Korea.

Instead, he spent time and money hiring artists to help create his own anime adaptation of the Lewis Carroll fantasy “Alice in Wonderland,” with which he seemed fascinated. At one point, he joined a debating class that helped Koreans converse in English, but rarely spoke.

“He was just a mysterious character. He said nothing unless I asked questions,” said Hur Sung-doh, who organized the weekly group debate.

Miller was arrested in North Korea in April this year for tearing up his tourist visa after entering the country with a tour group. He was sentenced to six years of hard labor last week.

North Korea is a magnet for adventurous foreigners, whether Christian missionaries, curious tourists or individuals drawn to the world’s most isolated nation.

One of the last outposts of the Cold War, North Korea is open to but suspicious of Western visitors, and any out-of-the-ordinary behavior by tourists is quickly investigated.

The U.S. government advises its citizens against travel to North Korea.

U.S. missionary Kenneth Bae is serving a hard labor sentence in North Korea after being convicted of crimes against the state. Another American, Jeffrey Fowle, was arrested for leaving a Bible in the toilet of a sailor’s club in the northeastern port city of Chongjin, and is currently awaiting trial.

On Tuesday, South Korean Marines arrested an American man who had been swimming in a river that flows toward North Korea and said he had been trying to go to the North to meet its leader, Kim Jong Un, Korean media reported.

Miller exhibited some unusual behavior in Seoul, but nothing linked to North Korea, his acquaintances said.

To Hur, the English-language teacher, he wrote in 2012 in response to an advertisement: “My name is Preston and I have been in Seoul for about 6 months. I am a student from London and saw (your) post.”

Hur said of Miller: “He said he studied journalism and was engaged in newspaper publishing, although I am not sure if he really did that job.”

In a televised interview with CNN last month, Miller spoke with a slight British accent and refused to answer questions on his motivations to travel to North Korea.

Miller’s family has not spoken publicly about him, and neither have any neighbors or friends he may have had in the United States. Those who met him in South Korea only recalled a slightly odd, quiet young man who gave little away.

“It was very curt and very awkward, speaking to him,” said Mike Stewart, a Seoul-based artist’s studio director who met Miller last year, when he received an e-mail from “Preston Somerset,” which Miller later said was a pen name. “He seemed very birdy, like ready to bolt at any minute, like he didn’t know what to say and things like that.”

Miller inspected space that Stewart was leasing to local artists and paid hundreds of dollars to rent a studio but never returned. “He gave me a good chunk of change — and then I never saw him again,” said Stewart, who runs the Jankura Art Space, in which Miller had planned to exhibit work from an artist he had commissioned to help create his own spin-off of “Alice in Wonderland.”

Francis Cole — an American who produces Japanese-style erotic art — said on a freelancing website that he was one of several artists, writers and musicians whom Miller commissioned to help produce his own Alice-inspired fantasy tale in the style of a Japanese anime.

Miller, under his Preston Somerset alias, and Cole, with the user name “Eirhjien,” were members of the deviantArt.com community, where people can post and share user-made artwork.

He recruited a gaming programmer to produce music for him, artists to draw men dressed as Cheshire Cats, and a ghostwriter to help piece the whole thing, named “Alice in Red,” together, according to posts on the deviantArt website.

“I vividly remember that he wanted it to have an ‘Alice in Wonderland’-like feel,” one of the ghostwriters, who was paid $200 to write for Miller, said via e-mail.

Miller identifies himself as Preston Somerset on several social media websites and cites steampunk, a genre of science fiction, and the Japanese vocal synthesized “humanoid” Hatsune Miku as some of his interests. He lists British writer George Orwell and Irish poet Oscar Wilde as two of his favorite writers.

It is still not clear what happened in the months between Miller’s quest to self-publish his own version of “Alice in Wonderland” and his decision to go to North Korea.

Photographs from Miller’s trial in Pyongyang showed a page from his notebook that said he had been “involved” in WikiLeaks and had attempted to access files from U.S. military bases in South Korea. Another page appeared to show a list of places in which Miller had spent time over the years — including London.

The Japan-based Choson Sinbo newspaper, which is loyal to Pyongyang and whose reporter attended Miller’s trial, said he told the court he lived in Seoul, and that he was unemployed.

The paper said Miller had promised North Korean authorities he could reveal U.S. state secrets “as if he was Edward Snowden.”