Chilean authorities announced on Friday the arrest of a firefighter and a forestry official suspected of igniting a blaze that claimed 137 lives in the resort city of Vina del Mar in February.
 
"An arrest warrant was issued today against the person who started the fires in February in the Valparaiso region," where Vina del Mar is located, police director Eduardo Cerna told a news conference. 

Shortly after, the Valparaiso regional prosecutor's office confirmed the arrest of a second suspect, an official of the National Forestry Corporation (Conaf), the entity responsible for combating forest fires and overseeing national parks.

Both individuals will be held in custody on Saturday, facing charges of arson leading to fatalities.

Read next: Chile forest fires kill 16, destroy 88 homes: Officials

On February 2, multiple fires erupted simultaneously around the coastal city of Vina del Mar, located 70 miles (110 kilometers) northwest of Chile's capital, Santiago. Fueled by winds and a heatwave with temperatures soaring to around 40 degrees Celsius (104 degrees Fahrenheit), the inferno became the second deadliest in the world this century.

Local media sources reported that the firefighter is a 22-year-old man who joined the volunteer force approximately a year and a half ago.
 
"We are completely devastated by what happened, it is a totally isolated incident... we have served Valparaiso for more than 170 years and cannot allow such things," Vicente Maggiolo, commander of the 13th Fire Company of the city of Valparaiso, told reporters. 

'An intentional attack' 

Ivan Navarro, chief of the environmental crime investigation authority, stated that detectives reconstructed the actions of the arrested firefighter before, during, and after the fire.
 
"We were able to determine the exact locations where the fires broke out and find the device that started them," he said, adding "We were also able to determine the involvement of a second person, accused of being the mastermind behind the arson." 
 
"He provided him with the knowledge to make these devices and also told him the exact times he needed to operate so that the fire would do more damage," Navarro said. 
 
Public Ministry investigators found the inferno started with small simultaneous blazes near Lake Penuelas, in the port city of Valparaiso next to Vina del Mar. Hot and windy weather quickly spread the flames. "There were approximately four outbreaks, equidistant from each other," prosecutor Osvaldo Ossandon said. 

Materials used to ignite the fire were discovered in the residence of one of the suspects, stated Navarro. Investigators were also examining potential connections to other instances of arson.

The motive behind the arson remained unclear.