A Colombian judge has convicted 15 soldiers over the killings of 10 undercover police officers in May 2006.
Colombia's fight against drugs involves different security forces
Judge Edmundo Lopez now has 15 days to sentence former Lt Col Byron Carvajal and the 14 soldiers who were under his command when the policemen were killed.
Prosecutors said Carvajal ordered the ambush of the anti-narcotics police near the southern town of Jamundi.
Carvajal said his troops were attacking leftist rebels who were working with drugs traffickers.
The authorities first said the deaths were accidental, with the soldiers mistaking the police for traffickers.
Officials later said inquiries suggested links between the troops and drugs gangs operating in the region.
The counter-narcotics police were working on a drugs operation near Jamundi when they were shot.
An informant, who was killed with the police, had told them at least 100kg (220 pounds) of cocaine were stashed at the scene of the ambush - a psychiatric centre - Associated Press news agency said.
Prosecutors have been urging the maximum of 60 years in prison for the convicted soldiers.
The town of Jamundi is in the Valle region, south-west of the capital, Bogota.
A long-running conflict in Colombia - the world's largest cocaine producer - between leftist rebels, security forces and right-wing militias has left tens of thousands of people dead.