Bomb Attack: Three explosions hit a bus carrying Borussia Dortmund football team

The explosion that hit the Borussia Dortmund team bus ahead of their Champions League quarter-final with Monaco was a targeted attack against the team, German police say.
The three explosions happened as Borussia Dortmund was leaving the L'Arrivee Hotel and Spa, about six miles or a 12-minute drive from the stadium, Signal Iduna Park, for a match against Monaco, which has been postponed.
The chief executive of a Dortmund, Hans-Joachim Watzke, said police informed him that the explosives that went off near the team bus were hidden by the exit of a hotel and detonated as the bus passed.
Defender Marc Bartra was injured in the explosion and was taken to hospital. Bartra underwent surgery on his right wrist, which was fractured during the incident, on Tuesday night.
The devices reportedly used to attack the bus were pipe bombs.
Police said they are hunting a car with foreign registered plates, which was seen near the crime scene shortly before the explosions occurred.
The 'special' construction of the explosives should afford investigators some clues in determining who might be responsible, according to the German newspaper Bild.
While investigators do not yet know the source of the explosions, police have confirmed that additional 'suspicious objects' were found at the Dortmund team hotel in the wake of the bus bombing.
A German prosecutor said Tuesday night that a letter found outside the hotel the team bus was departing from when the explosions happened 'takes responsibility for the act'.
Prosecutor Sandra Luecke said authorities won't give details of the letter at this stage, citing the ongoing investigation. The authenticity of the letter has not been verified.
Officers did not reveal the nature of the find but confirmed that a drone was deployed to assist in the search around the hotel.
Lange said officers are doing everything 'to provide security and that will be the case tomorrow, too'.
Gunnar Wortmann, a police spokesman, said: 'We will be working throughout the night to discover who was behind this attack. All police and vehicles in Dortmund have been mobilized.'
Dortmund Police Chief Gregor Lange told reporters late Tuesday that police decided at an early stage that the soccer team was the target of the explosions and are not excluding any possible angles in their investigation.