“The latest investigation shows that, in violation of the railway work rules, the accused switched on his mobile phone during his shift on the morning of the accident, started an online computer game and played actively for an extended period of time until shortly before the collision,” Mr. Giese said in a statement.

“On the basis of the timing, one must assume that the attention of the accused was diverted from regulating the traffic” on the railway, the statement added. “Because of this distraction, the accused made some false assumptions about where the trains might cross, gave the wrong signals to the trains and entered a false combination for an emergency call to the trains, so that the drivers never heard those signals.”

The dispatcher admitted to having played a game, but he told a court in Rosenheim on Tuesday that his attention had not been diverted, the statement said.

Björn Pfeifer, a spokesman for the state prosecutor in Traunstein, said that officials would not make any further statement on Wednesday.

The trains and the track involved in the February crash were fitted with an automatic brake system that was introduced in Germany after 10 people died in a similar rail accident in 2011.