According to the Truth and Reconciliation Commission, the unit is responsible for crimes committed against the Quechua population of the regions of Ayacucho, Apurimac and Huancavelica.

[4] The unit was first created during the first government of Fernando Belaúnde Terry as the 48th Command of the Civil Guard on June 21, 1965, in the town of Mazamari.

At that time the Revolutionary Left Movement, a guerrilla group led by Luis de la Puente Uceda, was operating in the province of Satipo.

However, in 1969 the unit was sent to Huanta in the Department of Ayacucho to put down widespread violent protests against the imposition of a charge of at least one hundred soles on those who failed a course.

[8] On September 5, 1979, peasants from the community of San Juan de Ondores occupied the lands of the Atocsaico estate, which had been taken over by the Cerro de Pasco Copper Corporation in 1926 and in the Agrarian Reform of 1969 was not returned to the community but rather handed over to the Túpac Amaru Agricultural Society of Social Interest, although in 1963 a court had annulled the sale of Atocsaico.

[13] In September 1982, the Sinchis arrived in two helicopters in Chalcos, presented themselves as protectors against the Shining Path terrorists and organized sports activities.

[14][15] One of the most well-known atrocities was the Socos (or Soccos; Quechua: Suqus or Soqos) massacre, a community in Huamanga Province, in which 32 men, women and children were murdered on November 13, 1983 by one unit of Sinchis.

Civil Guard Lieutenant Luis Alberto Dávila Reátegui, sentenced to no less than 25 years, was released on parole on April 5, 1991.