Investigators found near the scene a handwritten letter that claimed responsibility for the attack, prosecutor Sandra Luecke said. One explosive device failed to go off.
Dortmund police Chief Gregor Lange said police have not ruled out any possible motives for the attack, which led to the match being postponed until Wednesday night.
The team later said Bartra was in surgery for a broken radius -- a bone in the forearm -- and for "bits of debris lodged in his hand." He will not play Wednesday.
We hope that he will make a speedy recovery, Dortmund captain Marcel Schmelzer said on the team website. "The prevailing mood in the Black and Yellow camp seems to be to play the match tomorrow for Marc."
The team left its hotel about 7 p.m. local time (1 p.m. ET) for the UEFA Champions League quarterfinals match, a Dortmund police spokesman said.
Between 40 and 50 people, including the trainer and medical support staff, were on board the bus. A preliminary investigation indicates the explosives "could have been hidden in a hedge near a parking lot," according to an update posted on the Dortmund police website.
Our task now is to process this because in less than 24 hours we need to play, Dortmund CEO Hans-Joachim Watzke said, according to a CNN translation. "That’s our job. There is no alternative. It’s an unlucky situation but there is no other solution."
I was deeply disturbed by the explosions which occurred tonight in Dortmund. The decision taken to postpone the UEFA Champions League match between Borussia Dortmund and AS Monaco was the correct one since we must always prioritize the safety and security of all fans, team officials and players, Aleksander ?eferin, president of UEFA, European soccer’s governing body, said in a statement.
The match, which will be played at 18:45 CET (12:45 p.m. ET), is the first of a home-and-away series that will send the winner to the semifinals.