Investigators are examining a letter found near the scene of last night's attack on the Borussia Dortmund team bus.
German media are reporting the letter suggests possible Islamic extremist links to the attack, though it is not yet clear if the letter is genuine.
There are also reports about the existence of a second statement circulating online, in which an anti-fascist group claim they carried out the attack in retaliation for Borussia Dortmund not doing enough to distance themselves from rightwing populism.
Three explosions went off near the team coach on Tuesday night as it made it's way from the team hotel to the Champions League quarter-final tie with Monaco.
.@MarcBartra undergoes operation on arm and hand. Get well soon, Marc! https://t.co/sSmm76dGef pic.twitter.com/jylCuOPEGU
— Borussia Dortmund (@BVB) April 11, 2017
Defender, Marc Bartra, had to undergo surgery after he broke his wrist in the incident.
Borussia Dortmund's chief executive, Hans-Joachim Watzke, said the coach carrying the players had only just left their hotel and turned on to the road where the explosive devices were hidden behind a hedge.
The match against Monaco has been rescheduled for Wednesday evening with a 5.45pm kick-off.
