The Colombian authorities have re-established the country's elite police group known as the Search Bloc.
By Jeremy McDermott
BBC correspondent in Bogota
The squad was instrumental in destroying the drug cartels of Medellin and Cali.
Now their target is the last of the big cartels - that of Norte del Valle, whose leaders are wanted for extradition to the US.
It has been many years since the cartel-busting Search Bloc has been active in Colombia.
Farc rebels have plugged the gap in the drugs trade left by the cartels
It was this unit made up of elite police that gunned down the legendary head of the Medellin drug cartel, Pablo Escobar, in 1993 as he fled across roof-tops in Medellin.
Their new target, Norte del Valle, is based in south-west Colombia and is the last of the civilian drug cartels.
The Search Bloc's mission is to track down and capture the leaders of the cartel and seize their properties, which will then be sold by the state to raise much-needed revenue.
But should the Norte del Valle cartel meet the same end as the Medellin and Cali drug cartels, there will be little interruption in the flow of drugs from Colombia, estimated at 800 tonnes of cocaine and 10 tonnes of heroin every year.
Into the place of the cartels have stepped two organisations far more powerful and dangerous than the drug gangs -- Colombia's Marxist guerrillas and right-wing paramilitaries, who now between them dominate the drugs trade.