A 47-year-old man was arrested Sunday for allegedly threatening an organizer of a controversial Tokyo art exhibition that was to feature a statue symbolizing "comfort women" but was canceled due to protests, investigative sources said.

“Comfort women” is a euphemism for those who suffered under Japan’s military brothel system before and during World War II. They were forced or coerced into sexual servitude under various circumstances, including abduction, deception and poverty.

Takahiro Unemoto, a resident of Amagasaki in Hyogo Prefecture, is suspected of sending a threatening email five times from his mobile phone between June 19 and July 14 to one of the organizers of the "Non-Freedom of Expression Exhibition," according to the police.