A 28-year-old man was arrested Friday, accused of carrying out the attack on Borussia Dortmund’s bus in hope of profiting from a consequential fall in the club’s stock.

In a statement from Germany’s federal prosecutor, the suspect was identified as Sergej W., a German and Russian national charged with attempted murder, causing an explosion, and serious bodily harm. He allegedly bought a put option on Dortmund’s shares, giving him the right to sell them for a specific price at a predetermined date. A significant drop in the price would have been expected had any players been seriously injured or killed.

According to the Guardian’s Philip Oltermann, reports in Germany said that Sergej W. bought 15,000 put warrants for €78,000 and could have gained up to €3.9 million from a large drop in the price of Dortmund’s shares. The club is the only one in the country that floats shares on the stock market.

The attack occurred April 11 while Dortmund was traveling to Signal Iduna Park for the first leg of its tie against AS Monaco in the quarter-finals of the Champions League. Marc Bartra underwent wrist surgery after suffering non-life-threatening injuries to his right hand and arm.

Sergej W. was also a guest at l’Arrivee Hotel & Spa, where Dortmund players typically stay before playing at home. He booked a room from April 9 to April 13, as well as from April 16 to April 20, making the reservations before it was clear whether the club would be playing the first or second leg in Germany.

The faulty installation of the explosives may have saved the players’ lives. The first and last of the devices were installed near ground level, but the middle one was installed roughly one metre above the ground, too high to unleash its full effect. The bombs were filled with metal pins, measuring about 70 millimetres and weighing 15 grams. One was found 250 metres away from the blast.

Three identical statements were found at the scene of the crime, which claimed radical Islam was the motive for the attack. The two other statements subsequently appeared online, claiming far-left and far-right motives. But Islamist scholars and terrorism experts have significant doubts about the authenticity of the three statements.

Frauke Kohler, a spokesperson for the federal prosecutor’s office in Germany, explained how they were brought to the suspect’s attention.

“We’d like to think that the suspect is responsible for the attack on the team bus,” Kolher said in a brief statement to reporters, according to ESPN FC’s Stephan Uersfeld. “We were put on to the suspect’s tracks by suspicious option deals. He in total bought three different derivatives and gambled on falling stock prices.

“He bought the majority of the derivatives on April 11, the day of the attacks. The suspect took out a loan over several €10,000. His profit would have increased all the lower the stocks would have dropped. We can’t say right now how high the profit could have been exactly.”

Dortmund went on to lose the tie as Monaco achieved a 6-3 win on aggregate.

(Photo courtesy: Action Images)