#Dortmund bus attack: 1 detained, 'terrorist involvement' suspected

 German bomb attack on the bus of the Borussia Dortmund soccer team and are investigating a possible radical Islamist link, a spokeswoman for the federal prosecutor's office said Wednesday.

authorities suspect "terrorist involvement" in a 

The investigation is focused on two suspects from the "Islamist spectrum," spokeswoman Frauke Koehler said. Their homes have been searched and one has been temporarily detained, she said.

Three explosive devices shattered windows and injured a player on the Borussia Dortmund team bus Tuesday evening local time as the German squad was en route to its home Champions League match against AS Monaco.

The devices, which were hidden behind a hedge, contained pieces of metal and had a reach of 100 meters (109 yards), the prosecutor's office said.

Based on the type of detonator and explosive involved, German authorities assume "terrorist involvement" but the motives are unclear, Koehler said.

Letter threatens sporting figures, celebrities

One of two claims of responsibility for the attack -- found in three copies of the same letter left at the scene -- purports to be from an ISIS sympathizer, according to a copy of the document obtained by CNN from a source knowledgeable about the investigation.

The letter appears to have been written by a non-native German speaker or someone trying to pass themselves off as a non-native German speaker.

A second claim of responsibility, apparently from the far-left, has been circulating online, the prosecutor's office said, but there are doubts about it.

Source: CNN