COATEPEC HARINAS, Mexico (Reuters) - Bullet casings still littered the ground on Friday in Coatepec Harinas, a troubled municipality southwest of Mexico City where 13 police officers on patrol were brutally murdered in an ambush by suspected drug gang members.
Forensic teams and dozens of heavily armed police and military officials gathered at the cordoned off crime scene dotted with checkpoints after one of the worst mass slayings of Mexican law enforcement officials in years.
Though authorities say crime is widespread, residents were badly shaken by Thursday's violence. Some houses were strafed with bullets in the small town nestled between verdant hills and corn fields, where most people make a living cultivating crops.
The attackers rounded up bodies of the fallen police officers into a pile and continued to spray them with bullets, according to a local officer at the scene on Friday.
"They finished them off," said the officer, who declined to give his name. He had lost colleagues in the ambush, he said.
The police convoy came under fire in broad daylight as it patrolled about 40 miles (64 km) south of the city of Toluca, in a zone where gangs including the Familia Michoacana drug cartel are known to operate, officials said.
The area is in a region of the State of Mexico often hit by gangs from Guerrero and Michoacan, adjoining states that have long been among the most lawless in the country.
Local resident Guadalupe Flores heard the shooting right outside her window. She had just finished feeding her baby and, fearing for their lives, took the child and hid at the back of the house until the violence ended about a half hour later.
"I was terrified for my girl... It sounded horrible," the 26-year-old Flores said, pointing at the bullet casings in her driveway and bullet holes on the cement wall of her home.
The killings are another reminder of the task still facing President Andres Manuel Lopez Obrador, who vowed to pacify Mexico when he took office in December 2018, but has instead had to cope with even higher homicide levels than his predecessor.
On Friday, he said the perpetrators would face justice.
Federal authorities are investigating but have yet to give a motive for the killings. Another police officer at the scene said it may have been an act of "retaliation," without giving more details. Local police would not point to suspects.
One officer, a 27-year veteran with the State of Mexico police force, said the security situation in the country's most populous state has been in decline for the past decade.
Local police lacked sufficient training or proper equipment, including weapons, to address the security challenges, he said.
"And these are the consequences," he said, referring to his murdered comrades. He too withheld his name.
Juan Ramirez, 22, a local resident who works packaging fruit for export, said violence is a fact of life in the town.
"This is customary," he said. "Always afraid of a stray bullet."
(Reporting by Anthony Esposito, writing by Cassandra Garrison; Editing by Marguerita Choy and Alistair Bell)