A leader of Chile's indigenous Mapuche people convicted last week in the January 2013 arson deaths of an elderly couple was sentenced Friday to 18 years in prison.

Werner Luchsinger Lemp, 75, and his wife, Vivian Mackay Gonzalez, 69, died in a blaze at their farmhouse near Vilcun, a town in the southern region of Araucania.

Celestino Cordova Transito, a Mapuche "machi," or shaman, was arrested Jan. 4, 2013, hours after the deadly blaze.

He had a bullet wound in his chest when police encountered him near the Luchsinger farm.

Prosecutors had sought a life sentence with aggravating circumstances, which would have required Cordova to spend a minimum of 40 years behind bars.

The verdict and the sentence are "political," a spokeswoman for Cordova said Friday.

"The Mapuche communities and people are autonomous in determining how they will repudiate the (judicial) process," Kelv Tranamil said.

Defense attorney Pablo Ortega said he will review the verdict in detail before deciding on how to proceed.

"At the proper time, we will appeal to seek the absolution of Celestino," the lawyer said.

"Celestino was not convicted as the material author of the deeds, but rather for having - possibly - collaborated with the people who were in the act," Ortega said.

The deaths of Luchsinger and Mackay came against the backdrop of the "Mapuche conflict," which has seen indigenous militants in Araucania torch vehicles, highway toll booths and lumber shipments as part of a struggle to reclaim lands the Mapuches lost during a 19th century "pacification" campaign.

Those lands are now largely occupied by lumber and agricultural interests.

Mapuches make up around 650,000 of Chile's 17 million people and are concentrated in Araucania and greater Santiago. EFE