German police have arrested a man with dual Russian citizenship on suspicion of carrying out last week’s bomb attack on a Borussia Dortmund team bus in a plot to make money if the team's share price fell.
The 28-year-old dual German and Russian national, named only as Sergei W, is believed to have targetted the team for financial motives.
He had bought options on Borussia Dortmund stock in advance of the attack, hoping to make a profit as the share price fell, prosecutors said in a statement
The players' bus was leaving the team hotel for a Champions League match against AS Monaco on April 11 when three explosions occurred, wounding Spanish defender Marc Bartra and delaying the match by a day.
Sergei W was staying as a guest at the same hotel, where staff told on Firday how he had behaved suspiciously in the wake of the attack, showing no shock and ordering a meal in the restaurant while others tried to find out what had happened.
He had earlier demanded his room be changed to one facing the hotel car park — so prosecutors believe he could set off explosives by remote control as the team bus passed.
Even as investigators combed through the wreckage outside, he traded in Borussia Dortmund shares over the internet from his room, leaving a trail of evidence in the form of the hotel IP address.
He had bought 15,000 put options, or contracts giving him the right to sell Borussia Dortmund's shares at a pre-determined price, on the day of the attack, using a consumer loan he had signed the previous week.
“If the shares of Borussia Dortmund had fallen massively, the profit would have been several times the initial investment," the prosecutor's office said.
“A significant drop in the price would have been expected if players had been seriously injured or killed in the attack.”
More serious bloodshed was only avoided by what appears to have been a blunder on Sergei W’s part.
He planted three sets of explosives along the bus’ path, triggering them individually by remote control. But he placed the middle of the three too high above the ground, according to prosecutors.
The bombs were packed with pieces of metal shrapnel designed to tear through the sides of the bus. One two-inch piece was found 250 yards from the attack site.
Prosecutors claim Sergei W appears to have planned the attack well in advance. He booked rooms at the hotel for two separate dates, before it was clear when the match would be played.
Suspicion initially fell on Islamic extremists, after three letters were found near the attack site claiming responsibility in the name of Islamic State in Iraq and the Levant (Isil).
Proseuctors said experts who examined the letters had raised serious doubts over their authenticity.
They did not comment on press speculation that Sergei W may have forged the letters in order to deflect suspicion.
A separate far-Right claim of responisbility was made in an email to a German newspaper. Prosecutors said there were “contradictions and inconsistencies” in the email. There was no evidence linking the email to Sergei W, they said.
An Iraqi man was arrested in the wake of the attack, but prosecutors now believe he was not involved.
He is being held on separate charges that he was an Isil commander in Iraq prior to 2014.