MEXICO CITY — Authorities say a suspect in the killing of a Mexican investigative journalist has been freed after a court found he was tortured into confessing.

Regina Martinez was found beaten and suffocated in her house in April 2012. She was a correspondent for the respected investigative newsmagazine Proceso.

Authorities in the eastern state of Veracruz said she was killed in a robbery and suspect Jorge Antonio Hernandez Silva was sentenced to 38 years in prison. But colleagues accused the state of a cover-up, saying they suspected she was killed for her reporting .Her death became a rallying cry for press advocates pressuring the government to end impunity for journalists' killers.

An appeals court in Veracruz ruled Thursday that Silva was tortured into a confession, the only evidence against him.