The mutilated remains of up to a dozen people were found strewn across the northern Mexican city of Monterrey on Tuesday.
Messages left with the remains suggest the victims were killed as part of a purge within a gang.
Monterrey is the industrial and business capital of Mexico and the seat of many large companies.
Earlier this year, Tesla announced it would open a huge car factory in the city in 2024.
The discovery of the dismembered bodies at seven separate sites across Monterrey came after a drop in the level of violence in recent years.
In the early 2010s, a number of drug cartels fought for control of the city.
In their attempts to scare their rivals, the cartels would hang bodies from bridges or leave body parts next to signs warning off their enemies.
Local media said that next to the remains found on Tuesday were signs referring to attempts to infiltrate a cartel.
The messages were signed by the Cartel del Noreste (Northeast Cartel).
Police did not confirm the veracity of the messages but said that a cartel from neighbouring Tamaulipas state was behind the grisly dumping of the bodies.
The Northeast Cartel, which is based in Tamaulipas, is thought to have emerged from the Zetas crime syndicate.
Its leader, Juan Gerardo Treviño Chávez, was arrested by the Mexican security forces in March 2022 and deported to the United States.
It appears that since then, rival gangs have tried to infiltrate the cartel he led.
As well as drug trafficking, the Northeast Cartel terrorises migrants in its powerbase of Nuevo Laredo and Tamaulipas state.
It kidnaps migrants heading through Mexico to the United States and demands thousands of dollars from their families to release them alive. —BBC
