Following peace talks in Oslo, the Colombian president has said he is optimistic that a peace deal can be achieved with FARC rebels, ending almost 50 years of conflict.

However, Juan Manuel Santos said he was aware of potential threats to an agreement, which include drug and criminal gangs.

In the event of a peace deal, many Colombians fear thousands of demobilised FARC rebels will find it difficult to find jobs and could turn to cocaine trafficking.

But for some people in Colombia, drugs are a necessary evil, as Al Jazeera's Karl Penhaul explains in this exclusive report from Caqueta province.