Authorities in Mexico say a journalist has been murdered in Tijuana, the second killing of a media worker in the border city in less than a week and the latest in a string of killings in one of the world’s most dangerous countries for reporters.

Lourdes Maldonado Lopez was attacked on Sunday “with a firearm while she was in a vehicle” in the city, which borders the United States, according to the prosecutor’s office of the state of Baja California.

The killing comes less than a week after photojournalist Margarito Martinez was found dead with a gunshot wound to his head near his home in Tijuana. A local media rights group said Martinez had received threats from people connected to organised crime prior to the killing, although it remained unclear if the shooting was related to his work.

Maldonado Lopez, who had worked for several media outlets, had two years ago asked Mexican President Andres Manuel Lopez Obrador for “support, help and justice” as she feared for her life, according to a video republished on social media after news broke of her assassination.

Maldonado Lopez appeared to be referring to an ongoing lawsuit against her former employer, news organisation Primer Sistema de Noticias, which is owned by a former Baja California governor.

She won the lawsuit, which alleged unfair dismissal, days before her killing.

A source with knowledge of the case told Reuters news agency that Maldonado Lopez had previously been registered in a government protection programme for journalists, which included some police surveillance of her home.

Rights groups condemned the killing, with the Committee to Protect Journalists (CPJ) calling on authorities to “thoroughly and transparently investigate the attack.”

The group wrote on Twitter it was “shocked” by her murder.

Media rights watchdog Reporters Without Borders regularly ranks Mexico as one of the deadliest countries in the world for reporters, alongside Afghanistan and Yemen.

The violence is regularly blamed on powerful drug cartels that kill to discourage journalists from investigating, or generally reporting on, their dealings or connections to officials.

From 2000 to 2021, human rights group Article 19 has registered 145 killings of journalists in Mexico, with seven murdered in 2021.

A memorial for Margarito Martinez, a Tijuana-based photojournalist, who was shot as he left his home on January 17 [File: Gregory Bull/The Associated Press]

Rights groups have also called on authorities to investigate a fatal stabbing attack earlier this month that led to the death of journalist and social media activist Jose Luis Gamboa in the eastern state of Veracruz.

Investigators have not yet said if that killing was related to Gamboa’s work.

A media worker was also non-fatally stabbed in Yucatan state in the country’s east last week, Jan-Albert Hootsen, CPJ’s representative in Mexico, wrote on Twitter.