An isolated indigenous tribe in the Brazilian Amazon is coming under threat from drug traffickers, according to Brazil’s National Indian Foundation.

According to the head of Brazil’s indigenous protection service, known by its acronym FUNAI, the tribe was first threatened in mid-July when drug traffickers from Peru launched an attack in their protected territory. The site is located in the southwest state of Acre, some 15 miles from the Peruvian border and over 200 kilometers from the nearest Brazilian city.

After that attack, Brazilian police launched an operation resulting in the August 3 arrest of Joaquim Antonio Custodio Fadista, a Portuguese national whom police believe is a cocaine trafficker, operating along the Brazil-Peru border.

On Saturday guards protecting the area discovered a camp, believed to have been used by to drug traffickers. At the camp they found mattresses, cartridge shells and a broken arrow, believed to have been taken from a member of the tribe.

The armed gang who attacked the protected area in late July were allegedly attempting to smuggle drugs into Brazil, crossing the territory of the indigenous tribe. Other reports indicate that drug traffickers may have made attempts to clear the area to grow coca, to be used to produce cocaine.