Mexico's drug violence has claimed tens of thousands of lives and left many families without closure, unsure if their loved ones are alive or dead.br br The fact that authorities have not identified most of the bodies in mass graves, coupled with the lack of information available to victims, has led many to believe that most of the bodies are ending up in unmarked graves in cemeteries.br br Al Jazeera's Monica Villamizar tells family's story from Mexico City.