Prosecutor to Charge Man in Polish Train Collision A railroad traffic controller's error was likely a key factor in the head-on collision of two trains that killed 16 people and he will face criminal charges, a prosecutor said Monday. The investigation so far indicates that the controller made a mistake while setting the mechanisms routing the trains, sending one the wrong way down the track at high speed, prosecutor Tomasz Ozimek said. He said the man will be charged with unintentionally causing a railroad accident. It was the first indication of what might have caused the crash Saturday night, Poland's most deadly rail incident in 22 years. More than 50 other people were injured in the accident, which left the front cars in a mangled heap and toppled several others. Rescue workers prepaire to remove a wagon from the crash site in Szczekociny, Poland, Sunday, March 4, 2012. Two trains running on the same track collided head-on in southern Poland late Saturday, leaving more than a dozen people dead and more than 50 injured in the country's worst train disaster in more than 20 years. (AP Photo/Alik Keplicz) Close A U.S. and a Russian citizen were among those dead. A regional train was on its correct track as it traveled to the eastern city of Przemysl to Warsaw in the north. The other train, an Intercity train traveling south from Warsaw to Krakow at 95 kph (60 mph), had been mistakenly diverted onto the wrong track. The suspect hasn't been charged yet because he is in a state of shock and under doctors' care. Another traffic controller has also been detained for questioning but has not been charged, Ozimek said. Neither man has been identified, in line with a law that safeguards the identifies of suspects until a court verdict. The announcement, at a news conference in the southern city of Czestochowa, came as the country began two days of national mourning for those killed in the crash near the southern town of Szczekociny. The Polish white-and-red flag was lowered to half-staff at public buildings and entertainment and sports events were canceled.