Today, police arrested a 28-year old man in Tübingen.
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.