The eight were attempting to settle in a community called Centro Tsomaveni in the San Martin de Pangoa district and were killed last week, said Marco Velasquez, the father of one of the dead men.
"I had to retrieve my own son's body," Velasquez told The Associated Press by phone from the region. He said 42 relatives of the slain men had made the trip to recover their loved ones' corpses without assistance of police or soldiers.
Drug-trafficking remnants of Shining Path rebels who dominated the region in the 1980s and early 1990s remain active in the area. Peru's government gave shotguns to Ashaninka communities in those days to battle the Shining Path.
Velasquez said he did not know whether the slain men were involved in illegal logging or the planting of coca, the basis for cocaine, as Peruvian media speculated. He said two other men had survived and reached the town of Pichari after two days on foot.
He said he had proof of the attackers use of shotguns: empty 12-gauge shell casings.
Esperanza Ambrosio, the sister-in-law of a settler who disappeared in the attack, complained that police and soldiers spurned her pleas to search for him.
Local prosecutor Ida Romero told the AP that authorities were investigating the case.
Paula Acevedo, a spokeswoman for a group that seeks to protect Ashaninka communities in the region, said such killings could not be justified and called for an immediate investigation.
She said the Ashaninka in the Ene river area "have historically been forgotten by the state and live in communities transited by members of the last battalions of the Shining Path." She said there are also major problems with land tenure and a lack of property delineation.
The region is also a major cocaine cultivation and transit point.
A truth commission convened to study Peru's 1980-2000 conflict found that the Tsomaveni region was one of the worst affected by Shining Path violence. It said rebels had destroyed schools, killed community leaders and enslaved part of the population.