The German federal chief prosecutor has arrested a suspect of the Borussia Dortmund bus bomb attack and claimed the motive was to profit from a drop in share prices.
On the day of the attack, 11 April, he had bought a put option on Borussia Dortmund's shares, giving him the right to sell the shares for a specified price at a predetermined date.
The 28-year-old, who has dual German and Russian citizenship, faces charges of attempted murder, causing an explosion and inflicting serious bodily harm.
The Dortmund team bus was targeted with three bombs after it left a hotel to travel to the Westfalenstadion for the Champions League quarter-final first leg against Monaco.
"The explosive devices were detonated at the optimum time, " they said, noting that the team bus was equipped only with security glass and not reinforced glass.
The prosecutors said there were no indications that the suspect was aided by others.
FC's Raf Honigstein says that Borussia Dortmund's Champions League defeats were tainted by the attack on the team bus.
In March, the suspect booked a room for April 9-13 in the same hotel where the Dortmund team players were staying for their home game against Monaco AS.
The suspect bought three types of derivatives, with the suspicious trades leading authorities to the man, Frauke Koehler, the Federal Prosecutor's spokeswoman, said during a televised press conference on Friday.
Investigators ruled out a terrorist attack, saying that the man, identified as Sergei V., orchestrated the attack in an attempt to gain profit from a sharp decline in the football club's shares.
But German investigators last week said they had "significant doubts" that the attack on the Borussia Dortmund team bus on Tuesday was the work of "Islamists". A policeman on a motorcycle escorting the bus suffered trauma from the noise of the blast.
The fact that, aside from Bartra, "no others were wounded or even killed, was - as we know today - exclusively due to huge luck".
Dortmund captain Marcel Schmelzer said the team needed to learn all it could about the attack.
Soon after the attack, German police arrested one suspect with what were described as "Islamic links" after a letter was found close to the site of the bombings which started: "In the name of Allah, the Gracious, the Merciful", and claimed responsibility for the attack. "For everybody who sat in that bus, this information is important as it makes it easier to deal with it all".