When Spanish colonists arrived in Chile in 1541, they met fierce resistance from the native Mapuche people.

They were never able to conquer them, and after the War of Independence from Spain, neither could the subsequent Chilean state, so it reached an agreement, recognising the land south of the Biobio River in south-central Chile as Mapuche territory.

In the late 1800s, Chile began an expansion further south, sending in the army to clear the way for Chileans and European settlers and pushing the Mapuches off most of their land in a region known as the Araucania.

Fast-forward to present-day Chile, where roughly two-thirds of the 1.5 million Mapuches live in squalor in urban areas, and the remainder in poor rural communities.

They are the country's poorest and most marginalised segment of society, and unemployment and alcohol consumption are rampant.

But in the last two decades, a younger, better-educated generation of Mapuches has emerged to fight for their people's culture, language and rights. Some have formed organisations, such as the Arauco-Malleco Coordinator, to demand the restoration of their ancestral land and regional autonomy.

The campaign has included armed attacks against the "winka", or white farmers, setting fire to their homes and crops, occupation of land, and dozens of arson attacks against forestry companies.

The state has responded by applying a controversial Anti-Terrorism Law that dates back to Chile's military dictatorship.

"The long preventative custody clause benefits the prosecution because it generates commotion in society, because it is being said that terrorism is involved, and this is not true," said Karina Riquelme, a lawyer for many of the Mapuches being tried under the law.

Burned alive

While those who use or condone violence are in the minority, the majority of Mapuches support the cause of land restoration. And therein lies the problem: Under Chile's 1993 Indigenous Law, the state can give Mapuches land in areas where there is a conflict, after offering to buy it from its white owners.

"This encourages violence and conflict," said Jorge Luchsinger, a landowner and son of a couple burned alive when their farmhouse was set ablaze by armed men in 2013.

At the same time, the law does not allow Mapuches who receive land under Article 20B to sell or use their land as collateral, so they are not eligible for loans to buy farm equipment or other necessities to make their land more productive.

It is a long and seemingly endless conflict that is becoming increasingly tense.

"Here in the Araucania, people feel danger every day. Many can't sleep at night," said Alejo Apraiz, who lost two timber transport trucks in arson attacks.

Former President Sebastian Pinera, a conservative who is leading the polls for Sunday's presidential election, has vowed that if elected, he would apply harsher penalties to hunt down and prosecute "terrorists".

Sergio Catrilaf, one of 11 Mapuches recently acquitted under the Anti-Terrorism Law for the deaths of the Luchsinger couple, says he does not believe in violence, but insists the Mapuches will continue to fight for their land and autonomy.

"The origins of this conflict must be dealt with," Catrilaf said.

"There was a Mapuche nation here before the Chilean state arrived. We had and have our own organisation; there were agreements made and violated. These have to be addressed. We aren't the problem."