Mexico's special prosecutor for crimes against journalists says 67 journalists have been killed and 14 have disappeared in the country since 2006.
But Laura Angelina Borbolla, while testifying at a congressional hearing, said she was aware of only one case involving the murder of a journalist that resulted in someone being sentenced.
She said her unit had identified 74 suspects in reporters' killings, but she didn't say if any of them had been detained.
Press advocates have long called Mexico one of the most dangerous nations for journalists. But there is little agreement about the numbers killed.
According to the New York-based press watchdog, the Committee to Protect Journalists, 48 were killed or disappeared from December 2006 to the end of 2011, and five more were murdered this year. And Mexico's human rights commission lists 81 journalists killed since 2000.
None of the figures reflect incidents of threats and intimidation, either at a personal level or to media outlets. Armed attacks are relatively common in northern Mexico.
For example, on 10 July, there were three grenade attacks on newspaper buildings in a single day.
The targeted publications were El Mañana, a daily based in Nuevo Laredo; La Silla, the weekly supplement of El Norte, a daily based in Monterrey; and Linda Vista, another El Norte supplement produced in Guadalupe.
El Norte has sustained three similar attacks in the past two years, and the authorities have never identified those responsible.
© Guardian News and Media 2012
[image via Agence France-Presse]