Media rights groups are calling on Mexican authorities to thoroughly investigate the recent murders of three journalists in one week in the states of Oaxaca, Veracruz and Guanajuato.
"We are appalled by all these murders of journalists in Mexico," said Lucie Morillon, Reporters Without Borders program director. "Three deaths in a week — when will the violence stop?"
Morillon called on authorities in the three states "to ensure that impartial, independent and thorough investigations are carried out and that those responsible for these despicable crimes are arrested."
On Thursday, journalist Filadelfo Sanchez Sarmiento was gunned down by two men as he was leaving radio station La Favorita in Maiahuatlan de Porfirio Diaz in southern Oaxaca state.
Reporters Without Borders said Sanchez Sarmiento had received death threats.
"Mexican authorities must thoroughly investigate this killing and establish a motive, including any possible connection of journalism and bring those responsible to justice," said Carlos Lauria, Committee to Protect Journalists senior Americas program coordinator.
"This crime must not become one of the dozens of unsolved journalist murders in Mexico, which has one of the worst impunity rates in the world," Lauria said.
Elsewhere Thursday, Reporters Without Borders says the body of Juan Mendoza Delgado, a local news website editor in Medellin de Bravo, in the eastern state of Veracruz, was found in a morgue, a day after he was reported missing. The media group says Mendoza Delgado was reported to have been run over by a car.
Days before Mendoza Delgado's death, Veracruz Governor Javier Duarte had warned journalists to "behave themselves" and had accused them of being linked to organized crime.
In the central state of Guanajuato on June 26, the body of Gerardo Nieto Alvarez, the editor of El Tabano, a local newspaper was found in Comonfort with a neck wound.
Reporters Without Borders reports the prosecutor in charge of investigating Nieto Alvarez's death immediately ruled out any possibility of a link with his journalism.
However, the journalist's family told the rights group that they are convinced he was killed because of his work.
Nieto Alvarez's son told the media rights group, "My father's laptop has disappeared. It contained all the information he was going to publish. The prosecutor has not said anything about that."
Three other journalists have been killed so far this year in Mexico.
Reporters Without Borders says Mexico is the Western Hemisphere's deadliest country for journalists in 2015 and ranks it 148 out of 180 countries in its current press freedom index.
Mexico was ranked seventh on CPJ's 2014 Impunity Index, which spotlights countries where journalists are slain and the killers go free.
Some material for this report comes from AP.