A former Colombian justice minister has been arrested on suspicion of planning the assassination of presidential candidate Luis Carlos Galan in 1989.
Mr Galan's killing was Colombia's most notorious political murder
The ex-minister, Alberto Santofimio Botero, was arrested after new evidence emerged linking him to the killing, the attorney general's office said.
Mr Galan was gunned down at an election rally near the capital, Bogota.
At the time, the crime was linked to drug lord Pablo Escobar, and one of his associates was convicted for it.
Mr Galan, who was the Liberal Party candidate, had campaigned against corruption and drug-trafficking and was a political rival of Mr Santofimio.
After his assassination on 18 August 1989, he was replaced by his campaign manager, Cesar Gaviria, who went on to win the election.
Mr Santofimio was arrested in the coffee-growing central city of Armenia by government agents and accused of being the intellectual author of the crime, Colombian media reported.
Mr Santofimio was justice minister in 1974 and is a former member of both houses of the Colombian Congress.
Pablo Escobar's former head of security, John Jairo Vasquez Velasquez, alias "Popeye", is currently serving a sentence in a maximum security jail in connection with the assassination.
Colombian media reports say evidence from him and another Escobar associate, now dead, were instrumental in leading the authorities to detain Mr Santofimio.