German police have arrested a man suspected of detonating three bombs that were targeted at Borussia Dortmund soccer team bus in the hope of sending the club's shares plummeting and making a profit on an investment.

In a statement, the federal chief prosecutor said the 28-year old man, a dual German and Russian national identified as Sergei V., had bought options on Borussia Dortmund's stock before the attack.

The team bus was heading to the club's stadium for a Champions League match against AS Monaco on April 11 when the explosions went off, wounding Spanish defender Marc Bartra and delaying the match by a day.
Prosecutors last week expressed doubts about the authenticity of three letters left at the site of the attack that suggested that Islamist militants had carried it out.

The prosecutor's office said the suspect had bought 15,000 put options, or contracts giving him the right to sell Borussia Dortmund's shares at a pre-determined price, on the day of the attack, using a consumer loan he had signed a week earlier.

"If the shares of Borussia Dortmund had fallen massively, the profit would have been several times the initial investment," the prosecutor's office said.

Police detained the suspect in the city of Tuebingen in the south-western state of Baden Wuerttemberg. He faces charges of attempted murder, inflicting serious bodily harm and causing an explosion, the prosecutor's office said.

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.