Evidence points to the possibility that a researcher at the Institute of Physical and Chemical Research (Riken) may have been involved in industrial espionage, according to a report on an Riken investigation submitted to the education and science ministry Friday.

At the center of the case is Riken researcher Takashi Okamoto, who is charged with stealing genetic materials developed by the Cleveland Clinic Foundation of the United States while he was working there.

The researcher was studying Alzheimer's disease.

According to the Riken investigation report, a member of a research team headed by Okamoto said that a sample of genetic material he had received from the Cleveland Clinic Foundation before coming to Riken went missing after he began working at the government-funded institution.

It was also learned that Okamoto sent e-mail to another Riken researcher prior to leaving the U.S., asking whether there was an appropriate place to store genetic material in the event he wanted to send samples.

According to Riken officials, the researcher who received the genetic material from Cleveland said it was placed in a lab refrigerator for storage, but about six months later, it was gone. The researcher had joined Okamoto's team from another research institution, they said.

Riken refused to disclose what sort of material was sent from the Cleveland Clinic Foundation or whether the sender was Okamoto, citing the fact that the espionage issue has become a legal matter in the U.S.

Riken officials said they would set up another investigative team of lawyers to study more details of the case by the end of June.

Okamoto and another Japanese researcher, Hiroaki Serizawa, were indicted by U.S. federal prosecutors in mid-May on charges of engaging in economic espionage.