The suspect is a German national who lives in the canton of Aargau.
"He is suspected to be the backpack’s owner. He was detained on Sunday evening at his house", the police’s press release said.
Currently, there is no information about possible ideological motives.
The report comes after a suspicious backpack was found on 10 August on the Utoquai promenade in Zurich during the Street Parade electronic music festival. The content of the backpack was initially deemed to be dangerous and was sent to a forensic laboratory, which determined that it was fake.