The Russian authorities have charged the president of the St. Petersburg-based Arctic Academy, Valery Mitko, with high treason in an ongoing spate of similar investigations targeting Russian academics.
Mitko's lawyer, Ivan Pavlov, said on June 15 that the 78-year-old researcher had been under house arrest since February and his case was being investigated by the Federal Security Service (FSB).
Mitko is accused of transferring classified materials to China, Pavlov said, adding that his client had pleaded not guilty.
According to the lawyer, Mitko, who regularly traveled to China for teaching, had taken with him materials "exclusively related to his scientific and teaching activities."
Russian news agencies TASS and Interfax quoted unidentified sources as saying the scientist passed on information about hydroacoustic research and the detection of submarines.
On June 5, a court in St. Petersburg extended Mitko's house arrest until October 10. The scientist is barred from walking or communicating with others directly or via mail, the Internet, or telephone.
Treason charges against researchers and scientists have become a regular occurrence in Russia in recent years.
The news about Mitko comes four days after a Russian court granted early release to a 79-year-old former space researcher, Vladimir Lapygin, who was sentenced to seven years in prison in 2016 on a treason conviction and recognized as a political prisoner by the rights group Memorial.
Lapygin, who worked for a research branch of the Russian space agency Roskosmos, was also found guilty of handing classified materials to China, which he denied as well.