Prosecutors say no sign of 'terrorist background' to Dortmund attack

"Investigations carried out up until now have not given us any clues that there was a terrorist background to the attack," prosecutors said in a statement.

Letters left at the scene had suggested Islamist militants were behind the bomb attack.

Prosecutors said they believed suspect Sergei V., a German-Russian dual national who was arrested on April 21, carried out the attack "purely for monetary reasons".

(Reporting by Michelle Martin; Editing by Andrea Shalal)