MEXICO CITY — On a cold night in December 2009, three relatives in the Mexican state of Chihuahua were taken away by a group of armed men in military uniforms and were never seen again.

Now the Costa Rica-based Inter-American Court of Human Rights is examining the disappearances of the three civilians — Nitza Paola Alvarado Espinoza, José Ángel Alvarado Herrera and Rocío Irene Alvarado Reyes — for the first time.

Their story is part of a case that the court — an independent judicial body with legal authority in Mexico — heard over two days, ending Friday. It involves accusations of human rights violations by the Mexican military during government operations that began more than a decade ago to combat drug trafficking and organized crime.

The case sheds light on the broader impact that the militarization of public security has had on large parts of the country since troops were first mobilized for anti-narcotics operations in 2006.