The Tokyo High Public Prosecutor's Office placed a researcher in detention Monday in preparation for an examination into an extradition request filed by the United States, where he has been charged with industrial espionage.

Takashi Okamoto was taken to the Tokyo Detention House after Justice Minister Daizo Nozawa ordered prosecutors to examine the extradition request. They were to ask the Tokyo High Court to conduct the examination, sources said.

The high court will decide within two months whether Japan should hand the 43-year-old Okamoto over to the United States based on a bilateral extradition treaty, they said.