Which 120 Americans have been killed in Mexico? And why?

Only 35 Americans were reported murdered in all of Mexico in 2007 - 120 died there last year.
That's a huge increase, though the risks remain small given that an estimated 500,000 to 1 million U.S. citizens live in Mexico, about 14 million visited there last year.

A 2012 update is here:  http://www.chron.com/news/houston-texas/article/Number-of-Americans-killed-in-Mexico-continues-to-3518659.php

But the U.S. Department of State won't tell  us what they know about who died - or why..

In 2008-09, I spent months trying to mine Mexican public records, civil rights organizations, university researchers and newspaper archives to learn the names of those Am murder victims and determine what kinds of patterns contributed to an increasing number of murders in Mexico, particularly in border areas.  The U.S. Department of State provides updated figures every six months - but doesn't identify individuals or tell any of their compelling stories.
 
These cases reflect a small but important subset of a continuing wave of organized crime violence that has now affected many formerly very safe Mexican cities and states. As a result of my research, I found even in 2009 that many Americans had been slain by cartels because they were in the wrong place at the wrong time: fathers picking up their children; a woman going to get her hair done, children visiting grandparents, teens grabbing a burger or visiting family.

My original investigation is here: http://www.chron.com/news/nation-world/article/Killers-of-Americans-south-of-border-rarely-caught-1741056.php 

Last year, the number of U.S. citizen murders continued to grow.  .If you read other papers, you might assume the only American recently killed in Mexico was a jet skier shot by gunmen on a lake on the Texas-Mexico border. That one story got more coverage than almost any other murder, in part because the body remains missing. However, that same week, a U.S. college student visiting family in Mexico also was killed in a bus robbery-murder that got almost no coverage. The Houston Chronicle (and its sister paper the Express-News)  are the only newspapers that have regularly reported and investigated State Department stats to learn about these U.S. citizen murders.