Story highlights The dispatcher has been arrested on suspicion of manslaughter and gross negligence

The February train collision killed 12 people and injured 85, 23 of them seriously

The death toll rose Wednesday when a passenger injured in the crash died in hospital

(CNN) Moments before two trains collided head-on, killing 12 people, a dispatcher was playing a game on his phone, authorities said.

JUST WATCHED Train dispatcher was playing game on phone before crash Replay More Videos ... MUST WATCH Train dispatcher was playing game on phone before crash 01:16

Map: Bad Aibling, Germany

The dispatcher was arrested on suspicion of manslaughter and gross negligence Tuesday. German police said their investigation showed he had "violated operational rules" by playing the game until shortly before the collision on February 9

The dispatcher's actions, which distracted him from controlling the train traffic crossing in Germany's southern state of Bavaria, amounted to more than just a "temporary failure" and were rather a "dereliction of duty," investigators said.

The crash happened near the spa town of Bad Aibling, about 60 kilometers (40 miles) southeast of the Bavarian capital of Munich.

The death toll from the accident rose to 12 Wednesday when a 46-year-old man who had been a passenger on one of the trains died in a Munich hospital.

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