MEXICO CITY (AP) — Police found a woman’s decapitated body in a Mexican border city on Saturday, alongside a handwritten sign saying she was killed in retaliation for her postings on a social networking site.

The gruesome killing may be the third so far this month in which people in Nuevo Laredo were killed by a drug cartel for what they said on the internet.

Morelos Canseco, the interior secretary of northern Tamaulipas state, where Nuevo Laredo is located, identified the victim as Marisol Macias Castaneda, a newsroom manager for the Nuevo Laredo newspaper Primera Hora.

The newspaper has not confirmed that title, and an employee of the paper said Macias Castaneda held an administrative post, not a reporting job. The employee was not authorized to be quoted by name.

But it was apparently what the woman posted on the local social networking site, Nuevo Laredo en Vivo, or “Nuevo Laredo Live,” rather than her role at the newspaper, that resulted in her killing.

The site prominently features tip hotlines for the Mexican army, navy and police, and includes a section for reporting the location of drug gang lookouts and drug sales points — possibly the information that angered the cartel.

The message found next to her body on the side of a main thoroughfare referred to the nickname the victim purportedly used on the site, “La Nena de Laredo,” or “Laredo Girl.” Her head was found placed on a large stone piling nearby.