A former Colombian army officer has been found guilty of the forced disappearance of 11 people in 1985.
Colonel Alfonso Plazas Vega was sentenced to 30 years in prison for his actions as troops stormed the Palace of Justice in Bogota after it had been seized by left-wing rebels.
The 11 victims survived the military assault, but were taken away by the army and never seen again.
Human rights groups have hailed the judgement as a breakthrough.
"This is a historic judgement that ends 25 years of impunity," a lawyer for the families of the disappeared, Jaime Granados, told the BBC.
"It opens the possibility that people further up the chain of command will be investigated," he said.
The BBC's Hernando Salazar, in Bogota, says it is the most important judgement in Colombia since forced disappearance was made a crime in 2000.
The storming of the Palace of Justice, in the heart of Bogota, was one of the most dramatic incidents in decades of internal conflict in Colombia.
Thirty-five well-armed guerrillas from the now disbanded M-19 rebel group seized the Palace of Justice, home to the Supreme Court and next to the presidential palace and parliament.
They took judges hostage and planned to stage a political trial of then-President Belisario Betancur.
But the army attacked using heavy weapons, triggering a 27-hour battle that left the palace a burning ruin and more than 100 people dead, including several judges.
Col Plazas led the assault. The judges ruled that he was responsible for the forced disappearance of 11 survivors, most of whom worked in the building's cafeteria.
The case was opened in 2006 after video footage emerged showing some of them alive after the assault, being taken away by soldiers.
It became an emblematic test case for human rights groups in Colombia, where at least 20,000 people have disappeared in the last 30 years of conflict between government forces, left-wing guerrillas, and right-wing paramilitaries.