BERLIN (AP) — A Swiss man accused of spying on German tax investigators for his homeland will go on trial in Frankfurt next month.

Frankfurt's state court said Tuesday the trial of the 54-year-old, identified only as Daniel M. in line with German privacy rules, will begin Oct. 18 and is scheduled to last until Dec. 21.

The man was arrested in April in Frankfurt, Germany's financial capital. Prosecutors have charged him with espionage, saying he was paid to obtain information on tax officials in the German state of North Rhine-Westphalia between July 2011 and February 2015.

The state had purchased a stolen data CD containing details on German clients of Swiss banks, leading to numerous tax evasion cases. Switzerland expressed outrage at the move by its neighbor.