Gilberto Orejuela, the former leader of Colombia's drug trafficking Cali Cartel, died of lymphoma in a US prison while serving a 30-year drug trafficking sentence, his family said on Wednesday. Nicknamed 'The Chess Player', Orejuela was considered to be one of the world's biggest drug lords after Pablo Escobar's death in 1993. He was extradited to the US in 2004.