BERLIN (AP) – German prosecutors say they believe a radical Islamic terrorist group was behind an attempted bombing this week at a railway station in Bonn.

The device was found Monday and defused. It contained four butane gas cartridges, a metal pipe containing ammonium nitrate powder, three batteries and an alarm clock.

Federal prosecutors, who in Germany handle terrorism cases, announced Friday they were taking over the case. They say there is now sufficient evidence that the incident was an attempted attack by a radical Islamic group.

Prosecutors said in a statement there’s evidence a man suspected of leaving the bag on the station platform has links to Islamic radicals. They didn’t elaborate.

It still isn’t clear why the device failed to detonate.