Mexican authorities scoured a massive garbage dump Tuesday, searching for the remains of 43 students who have been missing for more than a month.
Investigating prosecutors suspect the open-air dump, surrounded by mountains in the Guerrero state town of Cocula, could be where corrupt local police delivered the captured students to hitmen linked to the local Guerreros Unidos drug ring.
"That is why experts are looking for remains carefully here. Bones already have been found, but experts have to look at whether they are human or from other animals," a federal government source close to the investigation told AFP.
The searchers, about 15 of them, were clad in white suits with air filters on their mouths, and were working with sniffer dogs.
They painstakingly designated a search area with small orange markers, but there was no definite sign of any human bodies.
Getting there was not easy. They climbed rocky trails dotted with small homes, goats and donkeys, to reach the dump for the town of about 15,000 people.
Scores of bodies have been found in unmarked graves in the search for the missing students, laying bare the extent of the rampant killings in the region, which law enforcement officials blame on ongoing drug violence.
It was not clear whether the bodies in a grave in the town of Cocula were those of the missing students, who vanished on September 26 in the nearby town of Iguala, after their buses were attacked by police.
The mayor of Iguala, some 130 kilometers (about 80 miles) southwest of Mexico City, and his wife, who are suspected of ordering the students' abduction, are currently on the run.
Around 40 municipal officers also have been arrested in connection to the disappearances.
Meanwhile, Guerrero's governor resigned last week, amid criticism he had not done enough after the disappearances.
President Enrique Pena Nieto said Guerrero's new governor, Rogelio Ortega Martinez, would meet with the country's top security brass to address the incident.
The 43 students went missing in Iguala after their buses were attacked by police and members of the Guerreros Unidos gang, killing six people.
Prosecutors suspect the young men were delivered by police to the gang, but do not know what happened to the students after that.
About 2,000 police and army troops are still combing the area by land and air, in the search for the students, so far without so much as a trace.