Police in the north-central Colombian city of Medellin are hunting the killers of 69-year-old 'cocaine queen' Griselda Blanco.

Blanco - who is thought to be one of the pioneers of drug trafficking to the US - was gunned down as she left a butcher's shop in the city.

Police said they had no evidence she had re-offended since her return to Colombia in 2004.

Inma Gil reports.