The FBI strongly believes a Japanese science institute was actively involved in an alleged act of economic espionage involving genetic materials on Alzheimer's disease, according to a declassified paper drawn up by an FBI agent.

In his affidavit, the agent said he came to suspect the involvement of Japan's Institute of Physical and Chemical Research (Riken) in the espionage after reviewing details of e-mail messages exchanged between Riken researchers and Takashi Okamoto, a former Cleveland Clinic Foundation researcher.

The affidavit, dated Aug. 27, 1999, was submitted to the U.S. District Court for the Northeastern District of Ohio. Its release marks the first time U.S. investigative authorities have disclosed documents in connection with the incident since making public the indictment papers.

The agent drew up the affidavit to request that the FBI be allowed to search Okamoto's U.S. residence and the files of three personal computers he used.