Javier Valdez, shown in 2013, was the sixth Mexican journalist slain this year. (Fernando Brito/AFP/Getty Images)

Journalist Javier Valdez long chronicled underworld activities in the Pacific-coast state of Sinaloa, home to the drug cartel once led by Joaquín “El Chapo” Guzmán. Valdez wrote on the cartel’s internal power struggles, profiled its players — everyone from capos to grunts — and untangled the unseemly alliances the traffickers forged with the government.

Valdez, 50, on Monday published the last of his weekly columns in Ríodoce, the publication he founded in 2003. He was fatally shot that afternoon as he drove away from the newsweekly’s offices in the state capital, Culiacan — a city beset by a battle for control of the criminal empire of Guzmán, who was captured last year.

Valdez was among Mexico’s most prominent journalists. His killing has shocked the nation, even as it experiences an upswing in homicides, with statistics showing Mexico on pace to experience one of its most murderous years in recent memory. Some media outlets decided to cease activities Tuesday in a show of solidarity with Ríodoce.

Valdez was the sixth Mexican journalist slain this year. His death came amid a wave of attacks against media professionals, who frequently resort to self-censorship to avoid attacks by criminal groups. Journalists often receive little sympathy from police and politicians — some of whom are in cahoots with the cartels

“The murder of Javier is one more link in a long chain of impunity,” said Javier Garza Ramos, former editor of El Siglo de Torreón, a publication whose offices have been shot at five times. Four of its reporters were kidnapped in 2013 and held for 10 hours. “Anyone who wants to silence the press can do it and have the confidence nothing will happen to them,” he said.

The Committee to Protect Journalists (CPJ) says that since 1992, at least 40 journalists have been killed in Mexico because of their work, while motives in the cases of 50 other reporters slain in the same period remain uncertain.

Ríodoce reported that Valdez was pulled from his Toyota Camry and shot 12 times in a daytime attack made to look like a carjacking. Police have no suspects. The federal attorney general’s office announced that it would investigate.

The gunmen “were going to kill him,” the newsweekly’s director, Ismael Bojórquez Perea, said in an interview. “There is no doubt about that.”

Valdez and his colleagues — particularly those who reported on the illegal drug trade — knew the risks involved in their work.

“We worked in fear, knowing that some day this could happen,” Bojórquez said. As word of Valdez’s killing spread, journalists rushed to the crime scene, crying, hugging and mourning the death of their friend in a state of “shock,” he said.

Valdez is perhaps the most high-profile Mexican journalist killed in recent years. He was honored with the CPJ’s International Press Freedom Award in 2011. His publication also received the Maria Moors Cabot Prize, awarded for outstanding journalism in the Americas.

Mexican politicians expressed regret for the killing and pledged protection for reporters.

“I reiterate our commitment to freedom of expression and the press, fundamental for our democracy,” President Enrique Peña Nieto tweeted.

The government recently replaced the special prosecutor tasked with investigating crimes committed against journalists. But critics say the office, set up to pull cases out of states where investigations are compromised by organized crime, has proved ineffective. It has won just three convictions since its creation in 2010.

One former lawmaker said the climate of fear created by attacks on the press suits politicians, who sometimes have surrogates harass reporters for investigating corruption or even mentioning criminal activity that could make public officials look bad.

“Politicians allow [attacks against journalists] to occur because they end up benefiting from the fear and terror that make journalists not publish their work, or self-censor,” said Gerardo Priego, the former lawmaker who led a special commission in Congress on protecting journalists.

Journalists, meanwhile, vented outrage over the killing of another colleague.

“6 journalists murdered in 2017. Zero arrests. Mexico without freedom of expression,” multiple journalists tweeted, using the hashtag #NiUnoMás, or “NotOneMore.”

Several journalists covering the illegal drug trade have come under attack in recent months. Miroslava Breach, a reporter for the national daily La Jornada, was killed March 23 in northern Chihuahua state as she drove her son to school. Norte, a local newspaper to which she contributed, subsequently closed, citing safety concerns.

Seven reporters, targeted last weekend in southwestern Guerrero state by an estimated 100 gunmen, were pistol-whipped and robbed. The reporters were eventually released.

Still, one photojournalist in Guerrero said he has encountered more challenges with the state than with criminals growing and smuggling opium poppies. The state government recently proposed an agreement with the media to minimize news on crimes and killings to protect the image of its main tourist attraction, Acapulco.

“I have never had threats from organized crime,” said the photojournalist, Alejandrino González, who freelances for international news agencies, “but I have had threats from the system.” The threats include intimidation from state police and being the subject of unflattering stories by journalists receiving state government money, he said.

Valdez expressed some trepidation at covering crime — assailants tossed a grenade at his office in 2009 — but also seemed uneasy with the government.

“I worry more about how the government responds than how the narcos respond,” he told the Mexico City daily Reforma last year.

Always upbeat, sporting thick glasses and a Panama hat, Valdez often assisted foreign correspondents reporting in Sinaloa. He was well known for his books on the drug trade and chronicles of life in a state where cartels came to be seen as big business and benefactors of the poor.

Reporters at Ríodoce wondered how the publication would continue without Valdez at the helm.

“We’ve been defeated,” one of them said. “It’s a stab in the heart.”

Samantha Schmidt in Washington contributed to this report.