Two drug squad detectives were gunned down Thursday in the northwestern city of Medellin, Colombian authorities said.

Sergio Antonio Castro and Franklim Ferley Moreno Lopez were attacked outside a theme park on the north side of Colombia's second-largest city, the National Police said in a statement.

"The police officers, dressed in civilian clothes, were waiting to meet with an informant," when they were shot by men traveling on motorcycles, the statement said.

Both of the slain detectives had a background in investigating financial crimes, the National Police said.

Medellin, home of the violent drug cartel led by the late Pablo Escobar, became one of the world's deadliest cities in the 1980s and suffers now from the depredations of gangs comprising former members of the now-defunct AUC federation of rightist militias. EFE