Story highlights Javier Valdez was known for his reporting on Mexico's drug wars

The Committee to Protect Journalists awarded Valdez the 2011 Press Freedom Award

(CNN) Mexican journalist Javier Valdez Cárdenas, who reported extensively on drug trafficking, was killed on Monday in Sinaloa, officials said. He is the fifth journalist to be killed in Mexico this year.

Riodoce, the weekly publication Valdez founded and worked for, reported he was shot to death. Valdez was a well-respected journalist in Sinaloa and published several books on drug trafficking, crime, and its effects on communities.

Javier Valdez: "I have told of the tragedy Mexico is living, a tragedy that should shame us."

Speaking Monday at the crime scene in Culiacán, Sinaloa state Prosecutor Juan José Ríos Estavillo vowed his department would provide more protection for journalists. According to the Committee to Protect Journalists, 40 journalists have been killed in Mexico since 1992.

Mexico President Enrique Peña Nieto tweeted out his condolences to the family and friends of Valdez. "I reiterate our commitment to freedom of expression and the press, which are fundamental to our democracy," Nieto said.

The Committee to Protect Journalists awarded Valdez the 2011 Press Freedom Award. "In a country where widespread self-censorship is the consequence of violence by drug syndicates and criminal gangs, Valdez still covers sensitive issues," CPJ wrote in its announcement of the award.

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