appear to have been taken in Japan in the late '80s and early '90s, when Ricks worked as an English teacher there.

　ということです。

http://edition.cnn.com/2010/CRIME/07/28/virginia.teacher.porn/index.html?eref=rss_crime#fbid=6HQ-xJ1qsPZ
Former teacher in Virginia facing child porn charges
Other pornographic images were found at Ricks' home in Federalsburg, Maryland, including some that appear to have been taken in Japan in the late '80s and early '90s, when Ricks worked as an English teacher there. Most of the boys depicted in the images appear to be incapacitated, according to the complaint

http://www.washingtonpost.com/wp-dyn/content/article/2010/07/28/AR2010072804535.html
In interviews with victims and their families, The Post found allegations of abuse that dated to 1978 in North Carolina and included cases in Japan, Danville, Federalsburg and, most recently, Manassas -- all locations where Ricks worked with children. The San Francisco case involved a student from Japan whom Ricks had taken on a cross-country U.S. vacation.