A German official says a combination of two blunders by a dispatcher appears to have led to a train crash that killed 11 people in Bavaria in February.

Two commuter trains collided on a single-track line near Bad Aibling Feb. 9. Investigators opened a criminal investigation against the dispatcher who they believe sent a wrong signal to the trains.

Bavaria's interior minister, Joachim Herrmann, told Tuesday's edition of Bild daily that when the dispatcher noticed his first mistake he tried to radio a warning to the drivers "but, possibly because he was agitated, he pressed the wrong button."

Herrmann said the message went to other dispatchers instead. The man then sent a second message to the drivers: "This time he pressed the right button, but it was already too late."