(CNN) -- The commissioner of Mexico's National Migration Institute has resigned, the state-run Notimex news agency reported.
No reason was given for the departure of Cecilia Romero Castillo.
Castillo took the job in December 2006. Superiors praised her efforts to restructure and modernize the institute and train immigration agents in human rights, the news agency reported.
It also noted, though, that her resignation came after the discovery in late August of 72 bodies of people who investigators believe were killed while en route to the United States. The bodies were found in the Mexican state of Tamaulipas.
Three people are believed to have survived the massacre. Officials said a preliminary investigation shows that the Zeta drug cartel was responsible.