Colombian prosecutors say a judge has sentenced 15 soldiers to as many as 30 years in prison for killing two brothers falsely identified as rebels killed in combat.

Officials say a captain, three subordinates and six enlisted men received 30-year terms for planning or taking part in the May 2006 killings in Medellin, Colombia's second largest city.

Five soldiers were also sentenced to four years each for helping to cover up the crime.

The brothers, Arley and Yon Cardona, worked as food vendors in Medellin and disappeared on May 25, 2006 when returning from a delivery. Their bodies were found the next day in a morgue and identified as guerrillas.

Human rights groups say the army has regularly executed civilians and passed them off as slain guerrillas to inflate their tallies of defeated enemy fighters.

U.N. Special Rapporteur for Extrajudicial Executions Philip Alston, a top United Nations human rights expert, recently described the practice as "cold-blooded pre-meditated murder for profit," following a 10-day investigation in June.

Colombian President Alvaro Uribe last year fired at least two dozen army officers, including three generals, in connection with the widening scandal. The country's top army commander General Mario Montoya also resigned.

The practice was uncovered last October when the bodies of 19 young men who had disappeared from a poor Bogota suburb were discovered in mass graves in the country's northeast.  The civilians were originally declared to be rebels killed during fighting.

Some information for this report was provided by AFP, AP.