A 28-year-old has been arrested in southern Germany as a suspect in the attack on the Borussia Dortmund team bus on April 11, the Federal Prosecutor's office in Germany confirmed in a statement.

The German-Russian suspect was arrested by a German federal anti-terrorist unit in the state of Baden-Wurttemberg on Friday morning and has been charged with attempted murder, causing a bomb explosion and aggravated battery, an official press release said.

The Federal Prosecutor's office in Germany says the man is suspected of having acted for financial reasons and had speculated on Dortmund's share value dropping after the attack.

Ralf Jager, the North Rhine-Westphalia state's minister of the interior, said the suspect had hoped to earn millions.

"The man appears to have wanted to commit murder out of greed," Jager said.

The statement from the Federal Prosecutor's office added that the suspect had booked a room in Dortmund's team hotel from April 9 through to April 13 and April 16 through to April 20, the time-frame during which a second leg would have been played at Dortmund had their Champions League quarterfinal draw necessitated it.

The Federal Prosecutor's office in Germany said that the three blasts had detonated at the time the bomber had intended, but that the second blast occurred around one metre above the ground, limiting the damage.

The bombs were filled with metal pins around 70 millimetres long, with one pin found 250 metres away from the blast.

Investigators from the Federal Prosecutor's office in Germany, the Federal Criminal Police and North-Rhine Westphalian state police had been following the lead after receiving information from the finance sector as well as from a bank suspecting money laundering, according to Spiegel, which broke the story early on Friday.

The day after the attack, German public TV station ARD reported that there had been an abnormality on the stock market just prior to the explosions with somebody buying options at the Frankfurt stock exchange.

ARD said that the buyers must "either have been extremely inexperienced or expecting a sharp fall in prices."

Last Tuesday, three explosions near the Dortmund team bus injured two people, including BVB defender Marc Bartra, and investigators later said that the attack could have caused major harm.

It was confirmed on Friday that one metal pin was found in the headrest of one of the seats in the last row in Dortmund's team bus. According to earlier reports, Bartra sat in the last row along with goalkeeper Roman Burki.

Following the attack, three identical letters were found near the scene of the attack and suggested a possible Islamist extremist motive, but investigators had doubts about their veracity. The Federal Prosecutor's office repeated on Friday that there are "strong doubts over a radical Islamist background" of the attack.

It added that another letter claiming the attack for a far-right background received by Berlin-based daily Tagesspiegel on April 13 also raised doubts, and could not be linked to the person behind the attack.

Dortmund CEO Hans-Joachim Watzke and club president Reinhard Rauball both expressed their gratitude to investigators.

"We hope that by arresting the suspect, the person responsible for the villainous attack on our players and staff members has been caught," the pair said in a joint statement on the club's official website.

Club captain Marcel Schmelzer added that the team hoped "to learn about the actual reasons behind the attack," adding: "For everyone on the bus this information would facilitate the process of coping with it."

Speaking on the club's in-house TV channel, sporting director Michael Zorc said: "My first thought is relief. I hope it helps processing the events."