MEXICO CITY (AP) — Authorities in Mexico’s Gulf coast state of Veracruz said Friday that a heap of bodies has been found piled on a roadside.

The state public safety department called the killings “a reaction to the results of work being done to fight crime.”

The department did not say how many bodies were found, but local media reported a total of nine dead.

According to those reports, a handwritten message found at the scene threatened authorities and was signed by “the four letters,” commonly a reference to the Jalisco Cartel. The cartel’s formal name, “Jalisco New Generation Cartel,” contains four letters.

The bodies were found in the township of Isla, Veracruz, near the crime-plagued port of Coatzacoalcos.

The grisly discovery comes one day after assailants left the bodies of eight men and two women in front of the governor’s office in the north-central Mexican state of Zacatecas.

The bodies were found crammed into a pickup truck left before dawn Thursday near a Christmas tree in the main plaza of the state capital, also named Zacatecas.

Francisco Murillo, the Zacatecas chief prosecutor, said seven of the 10 bodies had been autopsied and all died of “asphyxiation by strangulation.” Six had injuries suggesting they had their feet and hands bound. One showed possible signs of torture.

President Andrés Manuel López Obrador has been unable to significantly reduce homicides in Mexico. There were 31,615 killings in the first 11 months of 2021, a decline of just 3.6% from the 32,814 in 2020.