Chilean president Eduardo Nicanor Frei Montalva sought to defuse the situation through intermediaries and obtained the release of the policeman in exchange for dropping charges against students earlier arrested in the confrontations.

[10] During 1968, the MIR presence continued to be felt in various universities with armed actions increasing in 1969 through multiple acts of vandalism, intimidation and physical assaults on conservative/right wing students and faculty members.

On 2 May 1969, MIR activists operating in Concepción attacked the branches of National City Bank, the building of the La Patria newspaper and the offices of the Weigner Stein business.

In June 1969, the MIR kidnapped journalist Hernán Osses Santa María, Director of the Noticias de la Tarde in nearby Talcahuano (15.6 kilometres), in an effort to silence the in depth reporting on the leftist violence in Concepción.

A specially appointed judge was soon named and a criminal suit was filed with the Courts of Appeals of Concepción against the MIR and 13 of its identified leaders for breaking the Law of Interior Security of the State.

[11] The "fugitives from justice-list" consisted of Luciano Cruz, Miguel Enríquez, Marcello Ferrada de Noli, José Goñi (later Chile's ambassador to the U.S.), Nelson Gutiérrez, Aníbal Matamala, Bautista van Schouwen, Arturo Villabela and other five.

[27] In March 1973, 16-year-old Germán Enrique González and 17-year-old Sergio Oscar Vergara, both members of the Christian Democrat Party were killed while resisting the takeover of the La Reina estate.

[31] On 29 August 1973, a Mexican militant (Jorge Albino Sosa Gil) working in Chile, shoots and kills Second Lieutenant Héctor Lacrampette Calderón as the young army officer was waiting for a bus in the suburb of Providencia in Santiago.

[32] The next day, two farm workers (José Toribio Núñez and Celsa Fuentes) died of horrific burns after being caught in the bomb blast targeting the pipeline between Santiago and Concepción.

[45] On 23 October 1973, 23-year-old Army Corporal Benjamín Alfredo Jaramillo Ruz, who was serving with the Cazadores, became the first fatal casualty of the counterinsurgency operations in the mountainous area of Alquihue in Valdivia after being shot by a sniper.

By the end of the year, the Chilean police would claim to have uncovered a huge arms cache, that included 5,000 HK-33 sub-machineguns and corresponding ammunition numbering in the millions and large quantities of 20-mm anti-tank gun shells.

In 1978 the MIR sought to reestablish a guerrilla front in southern Chile and launched Operation Return which involved clandestine entry, recruitment, bombings and bank robberies in Santiago that briefly shook the military regime.

Several police, military and civilians caught in the crossfire and bomb blasts were killed in the renewed MIR attacks in the Chilean capital and at least 70 soldiers and policemen were wounded battling the marxist guerrillas.

The MIR spearhead was commanded by 30-year-old Miguel Cabrera Fernández (nom de guerre Paine), who along with 120-150 Chileans had completed their training for this operation in Czechoslovakia, Cuba and North Korea.

The Special Forces involved discovered the first guerrilla arms cache on 25 June killing Raúl Rodrigo Obregón Torres (nom de guerre Pablo) in the process, and four more store dumps were uncovered by the end of the first week in July.

On 16 October 1981, Juan Angel Ojeda Aguayo (nom de guerre Pequeco) who had escaped the mountain fighting was caught and executed while resting at his parents' home.

The Pinochet regime launched another counterinsurgency operation in August 1984 to wipe out the remaining guerrillas, concentrating in the areas around Concepción, Valdivia and Los Angeles, killing seven more MIR fighters and forcing the remainder to go into permanent hiding.

Another 41 supporting Mapuche that had earlier on taken part in the land and business takeovers under Salvador Allende were killed with 80 only spared after having been rounded up in and around Neltume and held for long periods in secret detention camps.

On 15 July 1980, three guerrillas in blue overalls and yellow hardhats ambushed the car of Lieutenant-Colonel Roger Vergara Campos, director of the Chilean Army Intelligence School, and killed him and wounded his driver in a barrage of bullets from AK-47 assault rifles.

In sweeps carried out from June to November 1981, security forces destroyed two MIR bases in the mountains of Neltume, seizing large caches of munitions and killing a number guerrillas.

[34] Leftist guerrillas, waiting in a yellow pick-up truck, ambushed on 30 August 1983 the governor of Santiago, retired Major-General Carol Urzua Ibáñez as he left his home, killing him and two of his bodyguards (army corporals Carlos Riveros Bequiarelli and José Domingo Aguayo Franco) in a hail of submachine-gun fire.

[81][82] On 6 August 1986, security forces discovered 80 tons of weapons at the tiny fishing harbor of Carrizal Bajo, smuggled into the country by the Manuel Rodríguez Patriotic Front (FPMR).

[85] On 5 November 1986, guerrillas threw an incendiary bomb into a bus in Viña del Mar, seriously injuring three women (Rosa Rivera Fierro, Sonia Ramírez Salinas and Marta Sepúlveda Contreras).

On 20 January 1988, a bomb planted by MIR guerrillas in the Capredena Medical Center in Valparaiso killed a 64-year-old female pensioner (Berta Rosa Pardo Muñoz) and wounded 15 other women.

[88] On 26 January, MIR guerrillas planted a bomb in a house in La Cisterna that killed 42-year-old Major Julio Eladio Benimeli Ruz, commander of the carabineros special operations group.

FPMR guerrillas that month killed 43-year-old Lieutenant-Colonel Miguel Eduardo Rojas Lobos of the Chilean Army, after he had parked his car in the Santiago suburb of San Joaquín.

[89] On 19 July 1988, leftists planted a bomb near a Church in Valparaíso, wounding three local churchgoers (Juan Salazar Olivares, Nelson Pérez and Luis Herrera)[90] In October 1988, several platoons of the Frente Patriótico Manuel Rodríguez take over four important towns throughout the country, Aguas Grandes, La Mora, Los Queñes and Pichipellahuén.

Within a few months after President Patricio Aylwin's accession to power, leftist militants showed that they remained committed to armed struggle and were responsible for a number of terrorist incidents.

[74] On 10 May 1990, two guerrillas wearing school uniforms killed carabineros Colonel Luis Fontaine, a former head of the antiterrorist unit of the carabiniers, Chile's national police force.

On 22 January 1992, two FPMR guerrillas (Fabián López Luque and Alex Muñoz Hoffman) were killed trying to rob a Prosegur cash delivery armoured van at the Pontifical Catholic University in Santiago.