A 54-year-old Swiss man was arrested on Friday in Frankfurt, Germany on suspicion of spying. He is accused of having spent five years spying for “a foreign power”, the German justice authorities say.

Several living and business quarters have been searched in Frankfurt and the surrounding area, the German Federal Prosecutor said in a statementexternal link.

The announcement comes following an arrest warrant issued by a judge at the German Federal High Court last December.

“The accused is strongly suspected of having worked for the secret service of a foreign power since the beginning of 2012,” the statement continued, without giving any further details of the foreign power.

The man was placed in remand custody on Friday after a hearing at the German Federal High Court, the Swiss News Agency reported.

Banking data?

Unconfirmed reports say the suspect had been working for the Swiss intelligence service to identify German tax investigators involved in the purchase of confidential Swiss bank client data.

Germany has in the past bought the names of Swiss banking clients to determine if they cheated on their taxes.

For its part, the Swiss Foreign Ministry said it was aware of the arrest of a Swiss citizen in Germany but did not give further information for data protection reasons.