The Zurich cantonal police have identified and arrested a person who sent an email threatening to bomb the canton’s highest court on Tuesday.

The man, who is a 44-year-old Swiss national, was arrested on Wednesday morning, according to the cantonal police. In response to a media request, the police said there was no connection with recent incidents or bomb threats in neighboring countries.

It remains unclear why the man sent an email threatening to use an explosive device in the high court building. An investigation has been opened to shed light on the matter. An explosive device was not found during the search of the building on Tuesday afternoon.

Court employees had to leave their workplaces after several media outlets in Zurich received an email, in which the sender threatened that an explosive device would go off in the courthouse in the afternoon. In the subject line he wrote “Allahu Akbar.” The man must now answer to the public prosecutor.