Three German citizens were arrested on Monday after Germany’s federal prosecutor accused them of being involved in transferring research on technologically advanced machine parts for ship engines to China’s secret service.

The suspects, whose names were listed as Herwig F., Ina F., and Thomas R., due to German privacy laws, were detained in the German cities Düsseldorf and Bad Homburg under suspicion of having worked for the Chinese secret service.

Herwig F. and Ina F. are a married couple who own an unspecified company in Düsseldorf that enabled them to contact various German researchers. Thomas R. is an employee of China’s Ministry of State Security, according to prosecutors.

“Thomas R. obtained information in Germany on innovative technologies that could be used for military purposes,” the statement said. “To do this, he made use of the couple Herwig F. and Ina F., who run a company from Düsseldorf. [Their company] served as a medium for contacting and collaborating with people from German science and research.”

The couple is believed to have arranged a deal with a German university on behalf of a Chinese organization to provide research information on combat vessel technology in violation of the German Foreign Trade and Payments Act. They are also alleged to have purchased a laser used for military purposes on behalf of China’s Ministry of State Security without authorization.

The arrests come a week after Chancellor Olaf Scholz urged Beijing to be more transparent over intellectual property theft and a slate of other issues.

This is also the second case of arrests in Germany over alleged spying within the last week. On Thursday, two men were detained in the German city of Bayreuth and were alleged to have been spying for Russia.

Prosecutors say that the two men are suspected of trying to sabotage aid to Ukraine and may have been plotting to blow up unspecified military infrastructure located in Germany.