Germany has been concerned about the threat posed by Chinese hackers seeking to steal information from the country’s companies, research facilities and ministries. But if sufficient evidence is found in the current case, it would be one of the first in years involving old-fashioned human espionage.

German officials were sifting through evidence gathered in the raids, which were carried out early Wednesday on nine homes and offices in Brussels and Berlin, as well as in the German states of Baden-Württemberg and Bavaria, Mr. Schmitt said.

The Chinese intelligence service is also involved in the inquiry, Mr. Schmitt said.

The German newsmagazine Der Spiegel, which first reported the raids, said that the three people targeted were suspected of passing private and social information to China’s ministry of state security.

Der Spiegel said that one of the three was a German national who had worked as a diplomat for the European Union until 2017, when he switched to a well-known consulting company. The other two work for a different consulting company, the report said.

Although some of the searched properties are in Brussels, a spokeswoman for the Brussels-based European Commission said on Thursday that none of its premises had been searched. She also said it had not received any requests to work with the German authorities or to hand over any evidence.