After the explosives attack on the Borussia Dortmund football team, police followed leads pointing to radical Islam, far-right hooligans and leftwing activists.
In the end, their investigations led them to an entirely new category of extremism: terror fuelled by financial greed.
On Friday, German police arrested a 28-year-old German-Russian national on suspicion of having carried out the explosives attack on Dortmund’s team bus in order to collapse the club’s share price so he could profit from stock market speculation.
Sergej W is also accused of having left behind several copies of a faked letter that tried to frame the attack as an act of Islamist terror.
The suspect was arrested by special operation officers on his way to his workplace at the University hospital in the southern town of Tübingen at 6am on Friday. On the day of the attack, 11 April, he had bought a put option – an option to sell assets at an agreed price on or before a particular date – on Borussia Dortmund’s shares, giving him the right to sell the shares for a specified price at a predetermined date.
Had the explosives killed a member of the team and the club’s share price dropped, the value of his put option would have increased significantly.
According to German media reports, Sergej W bought 15,000 put warrants for €78,000(£65,300) and could have gained up to €3.9m as a result of a large drop in Dortmund’s shares.
As outlandish as such a plot may first appear, it would explain why Borussia Dortmund became the first football team to be directly targeted by what looked like a terrorist attack: Dortmund is the only club in Germany to float shares on the stock market.
If the club’s share price had dropped by more than half after the attack, a speculator could have got a return of €1m on an investment of a couple of thousand euros.
Dortmund’s share price did drop temporarily after the incident, but only by 5%. After the suspect’s arrest on Friday, the club’s share price rose by 4%, from €5.46 to €5.58.