"It was an idea I initially had through localisation and telephony, and then I integrated it with a neural network," he said.

The system uses multiple drones equipped with different technologies, including thermal cameras that detect changes in temperature and humidity and tools designed to analyse conditions beneath the surface. The drones work together to identify and mark possible locations under collapsed buildings.

Villarreal said the technology was also adapted as bodies decomposed, with the system trained to identify indicators including bones, tissue, hair and nail residue.

According to Villarreal, his team has made more than 1,900 markings across affected buildings and may have helped locate hundreds of bodies, potentially approaching 2,000 by his own estimate.

Once a possible location is identified, volunteers and professional rescuers remove the rubble to verify the finding. "We have recovered family members and that has become a hope for many," Villarreal said, adding that the work is carried out voluntarily and families are not charged.

The team conducts much of its work at night, when reduced noise and interference are said to make some detection efforts easier.

The 53-year-old arrived in the badly hit coastal state of La Guaira shortly after the magnitude 7.2 and 7.5 earthquakes struck within a minute of each other on June 24.

More than 6,500 people were killed, while an unknown number of victims are still believed to be buried beneath collapsed buildings.

For Pacheco, the search has taken both a physical and emotional toll. After one exhausting day digging through debris, he struggled to breathe and briefly lost consciousness.

“The oxygen was slowly taken away from me until I kind of lost consciousness,” Pacheco told AFP.

“Everything went blurry and I thought of my young son before asking myself, ‘What’s going on?’”

When Pacheco first arrived in La Guaira, he immediately joined efforts to find a little girl trapped beneath a collapsed social housing complex.

He also remembers hearing a family trapped on the top floor calling for help.

“There were people screaming, asking us to help them,” he said. “I went where I was needed.”

Pacheco works with the Unified Rescue Group of Venezuela, or GRUV, a volunteer organisation that relies on donations. The group has rescued 21 people alive and recovered 56 bodies.

Pacheco said watching families continue waiting for loved ones still buried beneath the rubble has “profoundly impacted” him.

Authorities have not provided an official figure for the number of people who remain missing.

“When to close this chapter?” Pacheco asked.

“God willing, as soon as possible, so that everyone, so that those family members too, can find relief from the suffering they are going through, from not being able to recover their loved ones.”

Among those who have witnessed the rescuers' work is Frank Viloria, whose sister and niece died when their eight-storey building collapsed in Playa Grande.

“When I see him, I’m happy,” Viloria said after meeting Pacheco again.

“I’m very grateful to them. I feel a lot of respect and admiration; I can vouch for them because I saw how they work,” the 38-year-old added.

La Guaira, normally a popular weekend destination for people from Caracas, has been transformed since the earthquakes. Thousands who lost their homes are now living in makeshift camps.

For Pacheco, leaving the disaster behind has proved difficult.

“Sometimes I’m very sad; my mind is here... it’s never at home” in Caracas, he said.

“We’re going to keep going for as long as the body allows,” Pacheco said.