It occurred during a press conference convened and conducted by Edén Pastora, who at the time was the leader of a Contra guerrilla group fighting against the ruling Sandinista regime in Nicaragua.
In the years after the event, some journalists and activists, as well as the Costa Rican judiciary, pointed to the United States government's Central Intelligence Agency (CIA), which was seeking to direct the Contra insurgency against the leftist Sandinista regime in Nicaragua, as responsible for the bombing.
In 2009, Swedish journalist and filmmaker Peter Torbiörnsson revealed that he had been asked by Renán Montero, a Cuban military counter-intelligence officer working with the Sandinista Ministry of the Interior, to meet in Costa Rica with the man posing as Hansen and to escort him to the press conference at La Penca.
Torbiörnsson then attempted unsuccessfully to press charges in Nicaragua against Renán Montero, Lenín Cerna, and Tomás Borge (the Sandinista Minister of the Interior at the time of the bombing) for murder and crimes against humanity.
Those killed in the bombing were an American journalist, Linda Frazier; a Costa Rican cameraman, Jorge Quirós; his assistant, Evelio Sequeira; and four of Pastora's men.
[4] In 1986, the Christic Institute filed a US$24-million lawsuit on their behalf against several individuals all associated with Oliver North, including Rob Owen, John Hull, Richard Secord, Albert Hakim, and Thomas Clines.
Charges of murder were laid against Felipe Vidal, a Cuban-American CIA asset, and John Hull, an American farmer who lived in Costa Rica at the time[1] and had been previously named in the Christic Institute lawsuit.
[3] After the bomber had been identified as Gaguine, Swedish journalist, filmmaker, and La Penca survivor Peter Torbiörnsson broke nine years of silence and revealed that he had known of "Hansen"'s ties with the Sandinistas before the bombing.
[6] Years later, in 2009, Torbiörnsson admitted publicly that, in spite of his work as an ostensibly objective international journalist, at the time of the incident at La Penca he sympathized strongly with the Sandinista cause.