By Gael Favennec

CONSTITUCION, Chile: Barely three weeks after returning from Haiti, Cain was back home at work, furiously digging with his paws to track down the dead and missing, but now in Chile's massive earthquake.

The eight-year-old labrador combed furiously through the ruined homes in the Maule River Valley, searching for the remains of those who perished when monster waves hit Constitucion after Saturday's 8.8-magnitude quake.

Other dogs are trained to locate survivors trapped in the rubble of damaged buildings. But since he was a pup of just eight months old, Cain's speciality has been locating the dead.

"This kind of dog points to the place where they detect the smell of decomposing bodies," said Jose Carrasco Martinez, the master of the fair-haired canine.

Cain's rare skills were put to use in Haiti where more than 200,000 people are believed to have died in January's 7.0 magnitude quake.

Now he is back at work in Chile, his home country, where untold hundreds might have died in Saturday's quake and massive killer waves.

The dog eagerly sniffed along some stones Thursday, seemed to follow a scent, but then darted off in another direction.

Cain, who arrived with his trainer from Santiago on Sunday, has already found four bodies.

"In one house, he located two adults and two minors, buried in the rubble," Carrasco said. "We're working in places where people have told us that their loved ones have gone missing.

"We work in all kinds of disasters in Chile, but also abroad when foreign countries ask us for help."

After working in Colombia and Bolivia, Cain was sent to Haiti with his handlers on January 14, two days after the quake ravaged the capital Port-au-Prince.

"Our first mission was to find the wife of Chilean General Ricardo Toro, who was leading the UN mission in Haiti," Carrasco recalled.

"She was working out in the gym in the Hotel Montana, when the quake struck. We found five dead people there in more than seven days. Then we continued working around the hotel, and wherever Cain's help was needed." The dog and his handler spent almost a month in the Caribbean nation, after the quake which left more than 1.2 million people homeless.

"There everything was destroyed. But they don't use the same kind of materials there. Here most of the houses are made of earth but they stay standing. What did the most damage was the tsunami."

So far some 85 bodies have been found so far in Constitucion, a town of some 60,000 people. But hundreds of other residents are still missing, and Cain and his five labrador buddies still have a huge task ahead of them.

"I don't know how long we will have to stay," Carrasco added as they continued their grim task.