The trial is under way in Colombia of a former justice minister accused of planning the killing of a presidential candidate in 1989.
Luis Carlos Galan was a political rival of the accused ex-minister
Luis Carlos Galan was gunned down at an election rally in Colombia's most notorious political murder.
The ex-minister, Alberto Santofimio, was arrested last year after evidence emerged linking him to the killing.
At the time, the crime was pinned on 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.
The former minister is accused of ordering a hit squad run by Escobar to kill Mr Galan.
The main witness for the prosecution is Escobar's former henchman, Jhon Jairo Velazquez Vazquez, alias Popeye, who is serving a sentence in a maximum security jail for his role in the politician's murder.
He has alleged that Mr Santofimio urged Escobar to have Mr Galan killed.
The judge read out the charges against the former minister before a packed courtroom on Tuesday, with Mr Galan's widow and two children present.
"I've been made a scapegoat," Mr Santofimio said. "I reject these absurd charges from the deepest part of my conscience, with all my moral spirit."
His defence team is expected to urge the judge to call former presidents and political figures to testify on their client's behalf, Colombian newspaper El Tiempo reports.
They are also likely to try to undermine Velazquez's credibility, pointing to his own role in the murder and his decision to remain quiet for many years.
Mr Galan, a charismatic politician, was so far ahead in the polls he was virtually guaranteed victory.
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 justice minister in 1974 and is a former member of both houses of the Colombian Congress.