Firefighters in Ecuador said a rescue dog that helped save victims trapped under rubble after this month’s devastating recent earthquake died from heatstroke while performing his duties.

Dayko, a 4-year-old Labrador in the Ibarra fire department’s K9 unit, was part of a search-and-rescue team that has been working to find survivors following a 7.8-magnitude earthquake that rattled the country’s coast, about 100 miles from the capital of Quito. Officials said over the weekend that at least 654 people were killed and another 58 people were missing, according to the Associated Press.

It was Dayko’s job to help find them.

The fire department’s Facebook page is filled with photos showing a golden Labrador retriever crawling over and under debris, searching for survivors. Local news reports said the rescue dog saved seven people before his death.

The Ibarra fire department announced Friday on Facebook that Dayko had died after local veterinarians tried in vain to save him.

“We regret to inform you that the Ibarra fire service is in mourning because we have lost Dayko, who took part in the search at Pedernales,” the department said in a statement, translated by the BBC. “This four-legged friend gave his life in the line of duty. Thank you Dayko for your heroic efforts in Pedernales and in various emergencies where you were present.

“You held high the name of the K9 unit.”

On Monday, the department said an autopsy showed he died after suffering a massive heart attack and acute respiratory failure.

Because animals cannot sweat all over their bodies in the same way humans can, it is more difficult for them to regulate body temperature — meaning they are more susceptible to heatstroke in hot weather, according to Banfield Pet Hospital.

Without immediate treatment, the animal hospital said, such heat exhaustion can cause severe damage to the heart, liver, kidneys and brain — and ultimately lead to death.

Officials said Dayko had worked with the fire department in several locations around the country, from his home in Ibarra to the coastal towns.

His handler, Alex Yela, said Dayko “amazed everyone with his friendly character,” according to the statement cited by the BBC.