The Borussia Dortmund team bus is seen after an explosion near their hotel before the game. Photo: Reuters / Kai Pfaffenbach
The Borussia Dortmund team bus is seen after an explosion near their hotel before the game. Photo: Reuters / Kai Pfaffenbach
Dortmund players stand outside the team hotel after the explosion. Photo: AP Photo/Martin Meissner
Dortmund players stand outside the team hotel after the explosion. Photo: AP Photo/Martin Meissner
Forensic experts search the area where the expolsion occured. Photo: Reuters / Kai Pfaffenbach Livepic
Forensic experts search the area where the expolsion occured. Photo: Reuters / Kai Pfaffenbach Livepic

DORTMUND, Germany - Online postings linked to Germany's far-left have German investigators checking into whether those groups were behind the attack on the Borussia Dortmund football team bus.

Along with investigating a note at the scene that indicates an Islamist background to the attack, authorities are also looking at a series of Tuesday evening posts written in a style that is apparently common to Germany's far-left scene.

The online postings refer to the group manufacturing a series of bombs that went off as the team's bus passed by, an attack on a "symbol of the BVB," (the team's acronym). The comments argued that the team's management has not done enough to discourage racism, Nazism and right-wing populism.

Dortmund have had problems with some groups within their large fan base in the past, most notably at a February Bundesliga match with RB Leipzig in which Dortmund supporters attacked Leipzig fans ahead of the game and banners were held up with slurs and insults directed against Leipzig.

The ruling body DFB imposed a fine of 100,000 euros (107,000 dollars) and the closure of the 25,000-capacity stand for one league match.