Mexico City: An army lieutenant was sentenced to 31 years in prison, becoming the first person to be convicted in a Mexican civilian court for the crime of detaining somebody illegally, authorities said. The lieutenant illegally held the victim on May 20, 2012, in Los Herreras, a town in the northern state of Nuevo Leon, Judge Eustacio Esteban Salinas said in his ruling on Tuesday. The names of both the victim – who remains unaccounted for – and the officer were withheld. Besides the prison sentence, the now-former army officer was banned from holding any public post for 15 years. The lieutenant not only caused grievous harm to the victim and his or her family, he damaged the reputation of the army, Salinas wrote. “Regrettable and isolated actions” such as those of the officer in this case are contrary to the spirit of the military’s current role in law enforcement, the judge said. In 2006, then president Felipe Calderon gave Mexico’s armed forces a leading role in the battle against organized crime, a decision that was followed by an explosion in the number of deaths and disappearances.