While awaiting trial on criminal charges, Sprague died of a suspected heart attack.
They are awaiting trial on charges that include murder, torture and lesser violations of human rights.
More than a dozen other Mapuche leaders are awaiting trial on similar charges.
He died in jail when awaiting trial on charges of conspiracy to bomb private and government property.
Zardari was already in jail awaiting trial on separate charges.
The truck driver is awaiting trial on charges that carry the death penalty.
All three are in jail awaiting trial on various charges, including fraud and embezzlement.
A fourth is awaiting trial on related charges later this month and a fifth was arrested last week.
She talked to a group of 14-year-old boys and girls who are awaiting trials on drug-related charges.
Seven of those arrested were already in jail awaiting trial on other gang-related charges, officials said.