(CNN) -- The Inter-American Commission on Human Rights on Monday castigated Venezuela for its recent record on freedom of expression in a letter sent to the country's foreign minister.
At issue were three cases, including the conviction last week and sentencing of journalist Francisco "Pancho" Perez to nearly four years in prison and a fine of more than $18,000 for defamation of public officials.
The charges were brought over a 2009 newspaper column published in the city of Carabobo that shed light on many of the mayor's family members who were hired as contractors by the local government.
"The evident disproportion of the sentence handed down for the publication of a piece that was clearly in the public interest demonstrates the serious state of vulnerability in which freedom of expression in Venezuela finds itself," the commission said in a statement.
The letter, sent to Venezuelan Foreign Minister Nicolas Maduro, also highlighted the ongoing legal actions against Guillermo Zuloaga, one of the owners of the Globovision network, the country's sole remaining opposition broadcaster.
An arrest warrant was issued last week for Zuloaga and his son for the crimes of usury -- or charging exorbitant interest rates -- and conspiracy for having stored 24 vehicles on their private property. The charges are not related directly to Zuloaga's work at Globovision, but he and his network have been consistently facing legal challenges and accusations from the government.
The commission was concerned that the arrest warrants were issued just eight days after Venezuelan President Hugo Chavez publicly said that he was upset at the judicial branch that Zuloaga remained free. If the arrest warrants are politically motivated because of his ties to Globivision, it can constitute an attack on freedom of expression, the commission said.
A third case brought to the attention of Venezuelan authorities was a Molotov-cocktail attack on the headquarters of the media conglomerate Cadena Capriles. The attack took place in the context of public officials denouncing media outlets as destabilizing and anti-government forces, the commission said.
The letter in part read, "Spaces for public debate on Venezuelan government authorities are constantly becoming smaller, given the use of instruments like the criminal law to silence critical expression and dissent. In this sense, it is extremely worrying that a journalist would be convicted for the crime of 'disrespecting a public official' for publishing an article denouncing a possible act of corruption; or that the criminal law can be used as an indirect method of censoring the owner of one of the only media outlets in Venezuela that is independent of the government."
Chavez, who has publicly criticized the Inter-American Commission on Human Rights as a biased organization, did not immediately comment on the letter.