They were purportedly signed by the Knights Templar, a splinter cartel that surged in the state last year.
Calderon heads to Harvard
President-elect Enrique Pena Nieto, who takes office Saturday, has said he plans to take a different approach, focusing on reducing violence. He has offered few specifics about how his security policies will differ from Calderon's strategy, but he's said that change is coming.
"We will keep the policies that I think work," Pena Nieto said this week, "including cooperation with the United States to effectively fight organized crime."
As Pena Nieto prepared to take the reins this week, Mexicans learned the answer to a question that has been the subject of much speculation: Where will Calderon go, now that his term is ending?
Harvard University's John F. Kennedy School of Government announced Wednesday that the outgoing Mexican president will spend the next year as a global public leaders fellow at the school.
"President Calderon is a vivid example of a dynamic and committed public servant, who took on major challenges in Mexico," David T. Ellwood, the school's dean, said in a statement.
Hours after the announcement, a Mexican researcher who is studying ethics and corruption at Harvard this year said university officials should reconsider the move.
"I am alarmed that Harvard will protect a person as unethical as Felipe Calderon," Irma E. Sandoval wrote in a Twitter post.
Sandoval, who is a fellow this year at Harvard's Edmond J. Safra Center for Ethics and also heads a corruption and transparency research laboratory at Mexico's National Autonomous University, said she was hoping others at Harvard would join her in protesting Calderon's appointment.
The outgoing president, she told CNN, does not deserve the one-year fellowship.
"He is handing over a country in flames," she said.
At the end of the video released by the Mexican president's office Wednesday, Calderon strides down the steps of his official residence.
"As a citizen I will continue serving the country passionately until the end of my days, always grateful for the privilege I have been given to be Mexican. Many thanks, and see you soon, Mexico," the president says.
He looks up toward a flag, fluttering in the sky.