A suspected Islamic extremist has been arrested over the bomb attack on the Borussia Dortmund team bus, say German prosecutors.
The German Federal Prosecutor’s Office said three similar letters claiming responsibility found near the site of the attack before Dortmund’s Champions League match at home to Monaco on Tuesday night made an Islamic extremist motive possible.
It said that investigators had been focusing so far on two suspects from the “Islamic spectrum”, both of whose apartments have been searched. One has been arrested.
Three explosions occurred near the Dortmund team hotel as the squad were travelling to the Westfalenstadion for their quarter-final first leg, which has now been postponed until Wednesday night.
The explosives were hidden behind a hedge and were equipped with metal pins, one of which was found embedded in one of the headrests on the team bus. The blast area, prosecutors said, was more than 100 metres.
A statement from the Prosecutor’s Office said: “The terrorist background of the attack is based on the facts of the crime. The federal prosecutor has therefore taken the investigation. The exact motive of the attack is still unclear.
“At the site of the attack, three written claims of responsibility were found. After this an Islamic extremist background seems possible.
“Among other things the letters call for the withdrawal of Tornados from Syria and the closure of the Ramstein Air Base.”
Prosecutors pointed out it was still too early to make a final decision on the motive behind the attack, but did say there were “considerable doubts about the authenticity” of another claim of responsibility, from left-wing extremists.
Dortmund chief executive Hans-Joachim Watzke has urged his players to show their club does not bend to “terror and hatred” in an emotional changing-room address.
Watzke admitted the attack, which left defender Marc Bartra with a broken wrist, had left the team needing to come to terms with the “incomprehensible” very quickly.
And he said that when the team took to the pitch for the rearranged game they would be playing “for everyone – no matter whether Borussia (Monchengladbach), Bayer (Leverkusen) or Schalke supporters”.
Watzke said in a statement on the club website: “The BVB family was always especially strong when it had to cope with difficult situations. This is perhaps the most difficult situation that we have faced in the past decades. I am sure that we will show ourselves as a strong and united BVB like never before.
“We do not just play for us today. We play for everyone – no matter whether Borussia, Bayer or Schalke supporters. We want to show that terror and hatred can never dictate our actions. And of course we play for Marc Bartra, who wants to see his team win.
“We ask all BVB fans to support our team today with total energy for 90 minutes. This team had to process the incomprehensible in a short space of time. We should all help you to come to terms with it.
“I just appealed to the team in the changing room to show society that we do not bend before terror.”
Watzke took a phone call from German Chancellor Angela Merkel on Wednesday morning.
Merkel, the club said, “sees it as a very positive sign that the team does not buckle before terror, but plays on in the face of this difficult situation”.
Bartra underwent an operation on Tuesday night after breaking the radial bone in his arm and debris lodged in his hand as a result of the attack. The club said on Wednesday that he was “doing well in the circumstances”.
Goalkeeper Roman Burki was sitting at the back of the team bus alongside Bartra, and told Swiss newspaper website blick.ch how events unfolded.
Burki said: “We left the hotel at 7:15pm and went down the street. The bus turned down the main street, and there was a giant explosion.
“I was sitting in the back row next to Marc Bartra, who was hit by fragments of the broken glass.
“After the bang, we all ducked in the bus and those who could threw themselves to the ground. We did not know what had happened.”
The Dortmund players returned to their hotel following the explosions and trained on Wednesday morning ahead of the rearranged game, which will kick off at 1745 BST, with increased security measures in place.
The club warned fans to expect longer waiting times so to get to the stadium early.
They added that backpacks would not be allowed into the stadium and that all places to store them would be closed, so fans bringing them would be turned away.
German Football Association (DFB) president Reinhard Grindel, who had planned to attend Wednesday night’s clash between Bayern Munich and Real Madrid, will now be at the Dortmund-Monaco game instead.
He said in a statement: “It is important to me personally and in my position as DFB president to be in Dortmund today to show that all German football is united with BVB.”
UEFA said it would review the security arrangements for all of Wednesday night’s Champions League matches.
Atletico Madrid face Leicester in Spain in the third of three games.
A UEFA statement said: “Following last night’s incident in Dortmund, UEFA – in co-operation with the police, security services, stadium management and the clubs involved – is reviewing the security arrangements for tonight’s matches and security procedures will be enhanced accordingly wherever needed.”
Monaco fans left facing an extra night in Germany were offered accommodation by Dortmund fans via the hashtag #bedforawayfans on social media, while the club said on Twitter that all their supporters staying in Dortmund on Tuesday night would be reimbursed up to 80 euros (£68) by the club.
Monaco vice president Vadim Vasilyev described the attack as “despicable” and said: “Football should not be taken hostage by these individuals.”
Speaking on the club website, he emphasised his support for Dortmund and Bartra, praised Monaco fans for their “exemplary behaviour” and thanked German fans for their “generosity”.
He added: “We will help our players to get through this situation. Football will be stronger than this type of ignoble act.”
Monaco’s Ligue 1 match at home to Dijon on Saturday, which was due to kick off at 1600 BST, has now been put back to 8pm.