Police are still investigating the exact motive behind the attack on Tuesday, but have said there are two Islamist suspects - one of whom was detained - and that there is a possible "terrorist link".Three explosions rocked the Borussia Dortmund team bus on its way to a Champions League match against AS Monaco on Tuesday evening. Player Marc Bartra was injured with a broken wrist bone, while a police officer was also hurt amid the blasts.
Investigators examined two different letters claiming responsibility for the explosions - one found near the scene which used Islamist phrasing, and another posted online that seemed connected to far-left extremists.
Officials said in the afternoon that they had "significant doubts" about the supposed far-left letter, and the website where it was published has called it a fake.
The match planned for Tuesday was postponed and is set to begin on Wednesday evening with increased security measures, including a ban on backpacks inside the stadium.Read below for our live blog of coverage throughout Wednesday, and check here for a summary of what we know so far.
4.05pm - German media report further details on suspects.
The second letter of responsibility being investigated by police was most likely a fake.
“We think the letter was a Nazi fake,” the manager of the website Indymedia, on which the letter first appeared, told DPA.
“Neither the content nor the language fitted to a left-wing background, therefore we deleted it soon after it was published.”
Anyone can publish anonymously on Indymedia and are only later read by the site’s editors.
Police have still not officially ruled out a far-left motive to the crime.
"In the dressing room, I called on the team to show the public that we will not give in to terror," Hans-Joachim Watze said on Twitter, as the German club announced that the players had returned to training a day after the blasts.
Police guard the site of the attack. Photo: DPA
Around 30 police wearing bullet proof vests were added to the security detail at the Munich hotel where the Real team are staying due to Tuesday's blast in Dortmund.
Security remained tight throughout the night in Munich. According to German daily Bild, both the Real Madrid and Bayern Munich team buses were driven away to a safe place during the night.
Security will be tight at Dortmund's Signal Iduna Park with a crowd of 80,000 expected, likewise at Munich's Allianz Arena which is a 70,000-seater sell-out.
Bayern's head coach Carlo Ancelotti has offered Marc Bartra and Dortmund his best wishes.
"We give all our support to @BVB and wish @MarcBartra an early recovery," the Italian tweeted.
According to DPA sources, police are now investigating another letter claiming responsibility for the attack, this one purportedly from the far-left Antifa (anti-fascist) scene.
The letter was found on Tuesday evening online, and reportedly says that the attack was against the team because of what Borussia Dortmund symbolizes, namely racism, Nazis, and right-wing populism, the author says.
9.35am - Federal prosecutors take over the investigation.
They are set to release further details about the case early in the afternoon.
9.20am - Police examine letter with possible link to Islamists.
Police found a letter near the site of the blasts, claiming responsibility for the three explosions, which happened at 7.15pm on Tuesday evening, DPA and Süddeutsche Zeitung (SZ) reported on Wednesday based on information from police sources.
The letter begins with the words "In the name of Allah the merciful, the compassionate," according to SZ.
The letter also mentions a terror attack on a Christmas market in Berlin in December, and alleges that German Tornado military jets are involved in the murder of Muslims in the areas of Syria controlled by Isis.
The letter goes on to say that prominent people "in Germany and other crusader nations" are on "an Isis death list" until Germany withdraws its Tornado jets from the fight against Isis and a US military base in Ramstein, Germany is closed.
But investigators caution that it is too early to say if the letter is genuine or if it is meant to deceive the police into following a wrong line of enquiry, reports SZ.
Analysts, including experts on Islam, are now studying the letter's veracity.
The assault, described by Dortmund city's police chief as a "targeted attack" against the team, shook German football ahead of crucial Champions League ties.
German authorities have held off from describing it as a terror attack, saying it is too early to determine a motive.
But Germany has been on high alert since a series of jihadist attacks last year, including the Christmas market truck assault in Berlin in December that killed 12 people.
The explosives detonated immediately after the Dortmund team bus pulled away from the squad's hotel and headed for their quarter-final, first-leg, tie against Monaco.
Spanish international Marc Bartra underwent surgery on a broken wrist after he was hit by flying glass. A policeman, who was on a motorcycle and had been escorting the team bus, suffered trauma from the noise of the blasts.
Dortmund's quarter-final match will now be played on Wednesday evening, just hours before another Champions League clash in Germany between Bayern Munich and Real Madrid.
"We are assuming that they were a targeted attack against the Dortmund team," said the western German city's police chief Gregor Lange, adding however that it did not amount to an organised terror assault.
The bus had set off for the Borussia stadium about 10 kilometres away when "three explosive charges detonated" police said.
The explosive were hidden in a hedge and were detonated as the bus passed.
The blast shattered the bus windows and the vehicle was burned on the right hand side.
"The bus turned onto the main road, when there was a huge noise - a big explosion," Dortmund's Swiss goalkeeper Roman Burki told Swiss media.
"After the bang, we all crouched down in the bus. Anyone who could, threw himself on the floor.
"We did not know if more would come."
Burki said Bartra was "hit by splinters of broken glass". Dortmund's press spokesman said the 26-year-old had broken the radius bone in his right wrist.
The club said other players were safe and there was no danger inside the Signal Iduna Park stadium.
"The whole team is in a state of shock, you can't get pictures like that out of your head," Dortmund CEO Hans-Joachim Watzke said.
"I hope the team will be in a position to be able to compete tomorrow on the pitch.
"In a crisis situation like this, Borussia pulls together."
'Hard to absorb'
Germany's best-selling Bild daily quoted anonymous sources saying that investigators were hunting for a likely getaway car used by the attacker.
The vehicle had foreign car plates, said the newspaper, which also added that police believed the explosives were a particular type of pipe-bomb.
The announcement that the game was postponed was only made to the stunned stadium about 15 minutes before Tuesday's match was due to start.
Dortmund's president Reinhard Rauball said he believed the team would be ready for Wednesday's game.
"The players will be able to push this out of their minds and be in a position to put in their usual performances," he said.
"The worst thing would be if whoever committed this attack was now able to get to affect them through it."
But ex-Dortmund player Steffen Freund, who won the Champions League with Borussia in 1997, said there would be scars.
"When there has been a direct attack on the team bus, then it's not just forgotten by Wednesday," said the 47-year-old.
"Mentally and psychologically that is hard to absorb, it's a lot to deal with."
Dortmund police said security would be tightened at Wednesday's match, with a major deployment of officers to "ensure that the game is played safely".
Separately, security was also being tightened at the Bayern-Real tie in Munich.
Bild said both teams' hotels were under heavy police guard, and the squads' buses driven to a safe location.