Matthew Miller, the American sentenced to six years in a North Korean jail on Sunday, was working on an a cartoon interpretation of 19th century British novel Alice in Wonderland as recently as seven months before his arrest, a Reuters investigation into his background showed on Thursday.

While scant details were previously available on Miller, 25 of Bakersfield, California, the investigation revealed a lonely existence of at least two years in Seoul, South Korea, where the now prisoner expressed no interest in North Korea to acquaintances he met at a debating class designed for locals.