The covered photograph of an assassinated member of the Patriotic Union political party, which was launched by Colombia's Revolutionary Armed Forces (FARC), sits on a table during an event in honor of the victims of the nation's armed conflict in Bogota, Colombia, Oct. 18, 2012. Colombian government and rebel negotiators formally launched peace talks aimed at ending the South American nation's complex, nearly half-century-old conflict. William Fernando Martinez/AP
Jesus Santrich from the Revolutionary Armed Forces of Colombia, or FARC, waves a white handkerchief as Ivan Marquez looks on during a press conference on the sidelines of peace talks with Colombia's government in Havana, Cuba, Nov. 29, 2012. As Santrich waved the handkerchief, he said "one thing is to wave a flag in surrender, and another thing is to wave a peace flag." Franklin Reyes/AP
Police officers inspect a house that was damaged by home made grenades thrown by alleged rebels of the Revolutionary Armed Forces of Colombia, or FARC, near a police station in Suarez, in Colombia's southern state of Cauca, Nov. 12, 2012. Regional police commander Col. Ricardo Alarcon said that more than 20 people were slightly wounded by the explosions. Juan Bautista Diaz/AP
People walk by a burnt-out house in Caldono, in the province of Cauca, August 11, 2012. Indigenous authorities claimed that soldiers shot some native people, burnt a house and crops of coffee and suspect that the soldiers did so in retaliation against members of the Revolutionary Armed Forces of Colombia (FARC) guerrillas. Jaime Saldarriaga/Reuters
Accompanied by medical personnel, police sergeant Cesar Augusto Lasso (l.), and army sergeant Luis Alfredo Moreno, (with flag), gesture upon their arrival to an airport after being released by the Revolutionary Armed Forces of Colombia, or FARC, in Villavicencio Colombia, April 2, 2012. Fernando Vergara/AP
Members of the movement Madres de La Candelaria (Mothers of the Candelaria) are seen with photographs of disappeared family members during a protest in Medellin, March 15, 2013. The movement celebrates its 14th anniversary in their fight for their family members disappeared by the hands of paramilitary, the guerrilla FARC, ELN, and EPL and the army. According to the movement, 1,778 are counted as disappeared. Albeiro Lopera/Reuters
Colombia's President Juan Manuel Santos places transparent spheres containing messages appealing to the demobilization of FARC on the Orteguaza river in Caquetá December 21, 2011. The spheres are 14 cm (5.5 inches) in diameter with a small internal battery that lasts up to six days. Fredy Builes/Reuters
Army officers give condolences to Johan Martinez, 13, the son of slain rebel hostage, Army Sgt. Maj. Jose Libio Martinez, after a funeral Mass in Bogota, Colombia, Tuesday, Nov. 29, 2011. Martinez was among four hostages who were executed by their captors Saturday during combat between FARC guerrillas, and soldiers looking for them in the southern state of Caqueta. Johan never met his father, who was seized in 1997 and was the longest-held rebel captive. Fernando Vergara/AP
A police officer stands behind part of a display of 249 grenades seized in the municipality of Zarzal, during a news conference in Cali December 16, 2011. These grenades were seized from the Revolutionary Armed Forces of Colombia (FARC), according to the Colombian police. Jaime Saldarriaga/Reuters
A man dressed as a mime takes part in a nation-wide protest against violence and kidnappings, in Cartagena December 6, 2011. Outraged by the execution of four captives by FARC rebels, tens of thousands of Colombians protested across the nation to demand an end to half a century of guerrilla violence and kidnapping. Joaquin Sarmiento/Reuters
Soldiers and a sniffer dog prepare prior to departure from a military base in San Vicente del Caguan, in an operation to relieve troops in Caqueta state, a Colombian region with strong presence of the Revolutionary Armed Forces. Fernando Vergara/AP
A soldier runs through packages of marijuana on display for the press at the headquarters of the Army's Third Brigade in Cali, Colombia, Tuesday, March 11, 2008. According to the army seven tons of marijuana were seized from rebels of the Revolutionary Armed Forces of Colombia, or FARC, in Corinto, near Cali. Christian Escobar Mora/AP
Former hostage Ingrid Betancourt (c.) holds the hands of her children Melanie (l.) and Lorenzo after her children arrived from France to a military base in Bogota, Thursday, July 3, 2008. Betancourt, 3 US military contractors, and 11 other hostages were rescued by the Colombian military from rebels of the Revolutionary Armed Forces of Colombia. Betancourt was abducted by the FARC when running for president in Feb. 2002. Ricardo Mazalan/AP
An unidentified demobilized rebel of the Revolutionary Armed Forces of Colombia kisses her baby at a temporary shelter for fighters who surrender their weapons in Bogota, Monday, May 23, 2005. Javier Galeano/AP/File
A 2006 demobilization of Colombia's feared right-wing militias hinged on limited jail times for those who confessed their crimes. The government and FARC rebels are holding peace talks to end five decades of civil war.
When Carlos Mario Ospina joined a rightwing paramilitary group in 1997, Colombia's militias were just beginning to extend their writ in his province. To drive out leftist guerillas, they carried out a series of gruesome massacres, forcible disappearances, and murders, often in collusion with state security forces.