According to the Sueddeutsche Zeitung newspaper, police found a letter at the scene beginning with the phrase "in the name of Allah." The letter reportedly mentions Germany's Tornado jets killing Muslims part of the Daesh terror group (outlawed in Russia). The police however do not rule out the possibility that the letter, beginning with the phrase "in the name of Allah" is intended to confuse the investigators, the outlet suggested.
Borussia Dortmund said in a statement earlier on Wednesday that public prosecutor Sandra Lucke had reported the "discovery of a letter", which was being "checked in detail for authenticity."
Three explosions took place on Tuesday near the bus carrying Borussia Dortmund players. The explosions occurred in the Hoechsten district of Dortmund, some 9.6 kilometers (six miles) away from the Signal Iduna Park stadium where the UEFA Champions League quarter-final game against Monaco FC was expected to take place.
The earlier media reports suggested that Borussia player Marc Bartra and a police officer escorting the bus were injured in what the police called a "targeted attack" against the team. In the press release law enforcement said that according to preliminary data the explosives could have been planted in the fence near the parking lot.