Candido Rios, a crime reporter for a regional newspaper, was gunned down outside a convenience store.
Candido Rios, a crime reporter for a regional newspaper, was gunned down outside a convenience store in the eastern town of Hueyapan de Ocampo along with two other people, including a former police inspector, police sources said.
Rios, 55, had been under a government program designed to protect journalists and rights activists from a wave of deadly violence, said Jorge Morales, head of the State Commission for the Protection of Journalists in Veracruz.
More than 100 journalists have been murdered since 2006 in Mexico, one of the deadliest countries in the world for the profession, according to the watchdog group Reporters Without Borders.
More than 90 percent of the killings remain unpunished.
Rios was well-known locally for his decade-long career at the newspaper Diario de Acayucan, where he reported on crime and government corruption and had publicly feuded with several former mayors.
The newspaper's editor, Cecilio Perez, said Rios had received death threats from one former mayor, Gaspar Gomez.
"That mayor used to order him arrested and beaten, and would send him death threats. The threats made him quit journalism for a while, but he came back," Perez told AFP.
Perez described Rios as a born journalist -- a country boy who grew up poor and only finished middle school but talked his way into a job as a local correspondent, with a dual role as newspaper vendor.
Despite his humble background, "Pabuche," as he was known, made a name for himself with hard-hitting, detail-packed reports on organized crime and the misdeeds of public officials.
Perez said Rios was on his way back from writing his daily stories at an internet cafe when he was killed.
The victims also included Victor Acrelio Alegria, an ex-police inspector in Hueyapan de Ocampo, and a third person who had not yet been identified.
The gunmen opened fire with high-powered weapons, killing Acrelio on the spot and badly wounding Rios, who died on the way to hospital, police sources said.
Veracruz, a state dogged by drug cartel wars and corrupt politics, is particularly deadly for journalists: some 20 have been murdered here since 2010.
"Veracruz remains the most dangerous state to practice journalism," said Ana Cristina Ruelas, head of the press rights group Article 19.
"As long as there is no justice in these cases... attacks on the press in Veracruz will continue unabated," she told AFP.
Officials did not immediately disclose what sort of protection Rios had received under the so-called Mechanism to Protect Human Rights Defenders and Journalists.
Perez said he had security cameras outside his home.
The federal protection program, launched in 2012, offers different forms of protection ranging from bodyguards to panic buttons for journalists and activists who have been the victims of threats or attacks for their work.
It has been widely criticized for failing to stop the violence, which has only increased since its creation.
Last year was the deadliest yet for journalists in Mexico, with 11 murders.
And 2017 could be on track to surpass it, with 10 killed so far: Cecilio Pineda, Ricardo Monlui, Miroslava Breach, Maximino Rodriguez, Javier Valdez, Salvador Adame, Jonathan Rodriguez, Edwin Rivera, Luciano Rivera and now Rios.
Most of them had been reporting on powerful crime gangs and government corruption.
In May, President Enrique Pena Nieto vowed to strengthen protections for journalists and bring those who attack them to justice.
The pledge was in response to the murder of Valdez, an award-winning crime reporter and AFP contributor, on May 15 in the northwestern state of Sinaloa.
The state has been the scene of a bloody turf war within the powerful Sinaloa Cartel since its boss, Joaquin "El Chapo" Guzman, was extradited to the United States in January.
Violence has surged across Mexico since the government declared war on the country's powerful drug cartels in 2006. More than 380,000 people have been murdered and more than 30,000 have gone missing since then.