German police have arrested a 28-year-old German-Russian national on suspicion of having carried out the explosives attack on the Borussia Dortmund football team in order to collapse the club’s share price so he could profit from stock market speculation.

Sergej W was arrested by special operation officers on his way to work at 6am on Friday. 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. Had the explosives killed a member of the team and the club’s share price dropped, the value of his put option – an option to sell assets at an agreed price on or before a particular date – 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.(guardian)…[+]