A 72-year-old woman living near Villa Union's city hall recounted how she huddled with two of her grandchildren inside an armoire during the shooting.
The street in front of her home was littered with shell casings, and her walls and door were pocked with bullet holes.
"I'm still trembling," she said, speaking on condition of anonymity out of fear for her safety. "We've never seen anything like this. It was as if they just wanted to sow terror."
Around midday Saturday, armed men in a convoy of dozens of vehicles arrived in Villa Union and began shooting up city hall. Many of the vehicles were emblazoned with the cartel's initials — CDN, for Cartel del Noreste, or Northeast Cartel — as were the attackers' bulletproof vests.
Coahuila Gov. Miguel Riquelme said state security forces arrived within an hour and surrounded the town, about 35 miles (60 kilometers) southwest of Eagle Pass, Texas.
Sixteen gunmen were killed, along with four state police officers and two civilians, he said.
On Monday morning, the town of about 6,000 people was strewn with burned-out vehicles, and the city hall's facade was so riddled with bullet holes it looked like a sieve.
Workers swept up glass and rubble out front and began to plaster over the holes, while others collected important documents. Broken glass covered the floor, a crucifix had fallen from a wall, furniture was destroyed, and portraits of local politicians were pierced by bullets.
Outside lay a burned SUV, a shot-up ambulance and a yellow school bus with CDN spray-painted on the side.
Shops nearby cleaned up rather than open for business. Despite the presence of soldiers and federal police patrolling the quiet streets, no one sent their children to school, and residents did not want to give their names for fear the gunmen could return.
"They wanted to send a message" to the state government, Riquelme told the Mexican network Radio Formula.
He said the Northeast Cartel, based in nearby Tamaulipas state, has made 15 attempts to establish itself in Coahuila since he became governor two years ago.
"We have not permitted the entrance of these criminals in our entity," he said. "They thought they were going to enter, strike and exit, something that didn't happen."
The Northeast Cartel is an offshoot of the Zetas, a cartel with roots in elite military units. The Zetas long dominated Nuevo Laredo and Tamaulipas state and were known for military-style operations and grotesque violence intended to intimidate their enemies.
Villa Union is 12 miles (20 kilometers) from the town of Allende, the site of a 2011 massacre involving the Zetas in which officials say 70 died.
Villa Union residents wondered why their town was targeted with such fury. A woman who declined to give her name likened the attack to being in a war zone and said, "They caught us off guard."
The governor said that all hostages taken Saturday, including five minors, had been rescued. Cartel members had taken some locals with them as guides as they tried to make their escape along back roads.
Of the 25 vehicles seized, four carried .50-caliber machine guns. Dozens of homes were damaged.
On Monday afternoon, the family of a civil defense worker who was one of the two civilians killed in the shooting held a wake for the father of four children. Still terrified, all declined to speak or be identified. His widow said only, "He didn't do anything bad."
Mexico's homicide rate has increased to historically high levels this year. After a string of massacres, critics have charged that President Andrés Manuel López Obrador's government does not have a coherent security strategy.
López Obrador met on Monday with relatives of nine women and children, all dual U.S.-Mexican citizens, killed by gunmen from the Juarez cartel in the border state of Sonora on Nov. 4. Authorities said they have taken three suspects into custody in connection with the ambush.
The relatives expressed satisfaction with the meeting but said they want further investigation.