25 year old Tsutomu Nozawa has been arrested for sending threats to the website of Narita International Airport. Calling himself the "Sanrizuka Revolutionary Organization" (Sanrizuka is the name of agricultural area on which Narita is built) and the "Narita Volunter Army" Nozawa sent emails from the 19th April saying that he would attack the airport and on the 2nd May, he claimed he would strike within a month. He variously threatened to use poison gas and explosives. It turns out the man actually works for a public foundation called Airport Security Business Center which was set up in response to the hijacking of JAL 472 in 1977. It's more than a little embarrassing for that organization since one of their main responsibilities is doing background checks on airport security personnel as well as training and approving them for work. Nozawa himself is said to work in the department in charge of hand luggage inspection. Police believe he sent the threats from a Tokyo internet cafe. This report is more unwelcome publicity for airport security which was in the news recently for failing to locate drugs planted in a passenger's luggage as part of a training exercise.
From various news reports. Yomiuri article here (Japanese)