MEXICO CITY (AP) — As many as a dozen bodies were found Tuesday scattered around the northern Mexico industrial hub of Monterrey and its suburbs, including some of the wealthiest neighborhoods in the country.

Prosecutors in the state of Nuevo Leon did not give a final tally of the number of dead because some of the bodies had been found in pieces or were dumped in plastic bags.

But prosecutors confirmed at least seven bodies had been found, as well as five bags of body parts.

Drug cartels in Mexico often leave dismembered bodies on streets, often with banners threatening officials or rival gangs.

The grisly discovery came the day after drug cartel banners had been left around the city. It contrasted with Monterrey’s recent reputation for success after it was chosen as the site of a new Tesla car plant.

Monterrey suffered waves of drug cartel violence in the 2010s, but had become more peaceful until Tuesday’s events.