In a booklet by an Okinawan women's civic group documenting sex crimes by U.S. soldiers in Japan, a 9-month-old girl is listed as the youngest rape victim.

Among a litany of cases the group began compiling after the rape of an Okinawan elementary schoolgirl by three U.S. soldiers in 1995, the 1949 crime by a U.S. serviceman who was an acquaintance of the baby's mother stands out as arguably the most heinous and unimaginable — the baby reportedly died soon afterward.

But the acts of sexual violence by U.S. servicemen are likely to be even more extensive than research has so far uncovered, according to the group, called Okinawan Women Act Against Military Violence.