SANTIAGO, Chile — The killing of a young indigenous man by an antiterrorism police squad has intensified longstanding criticism over the treatment of native communities in southern Chile by the government and security forces accused of systemic abuses.

The killing of Camilo Catrillanca, 24, on Nov. 14 is the latest flash point in a fight over ancestral lands claimed by the Mapuche, which has led leaders in Chile to treat some indigenous land rights activists as terrorists — by for example, charging and trying them under antiterrorism laws.

Mr. Catrillanca, a Mapuche, was riding a tractor home after working in the fields near the town of Ercilla, in the Araucanía region, about 370 miles south of Santiago, the capital, when an antiterrorism police team approached him, apparently suspecting that he had taken part in a car theft.

According to a 15-year-old boy who was riding on the tractor, Mr. Catrillanca turned the tractor around and started driving away from the police when members of the squad, nicknamed the Jungle Commando, shot at them from an armored car.