Colombia was stunned by Wednesday's resignation of the Defence Minister, Fernando Botero, amid allegations that he had taken millions of dollars of Cali cartel money for Mr Samper's election campaign last year. Mr Botero, now under investigation by the Supreme Court, denied the allegations and said he was resigning to protect his honour.
Congress is already investigating Mr Samper's conduct at his own request and polls have shown that most Colombians believed he was lying in a television broadcast when he denied knowingly accepting drug money. US officials say privately they believe Mr Samper knew.
The talking point in Bogota was the early demise of Mr Botero. He is only 38, a Harvard graduate, the son of the world-renowned painter and sculptor Fernando Botero - and until now seen as a likely future president.
When a Botero sculpture of a bird was blown up in Medellin in June, killing more than 20 people, few Colombians doubted that the young Defence Minister was the symbolic target. The only question was whether the message came from the Medellin cocaine cartel, or the Cali cartel - whose leader, Gilberto Rodriguez Orejuela, had just been arrested - or from Marxist guerrillas.
According to testimony by Santiago Medina, Mr Samper's campaign treasurer who was arrested last week, Mr Rodriguez Orejuela's brother and cartel partner Miguel, who is in hiding, once boasted: "I own the smallest but most expensive Botero in the world." That, according to Mr Medina, was a reference to Mr Botero Jnr, who was Mr Samper's campaign manager, and Mr Medina's boss, when the cartel allegedly provided millions of dollars in cash to the campaign last year. According to Mr Medina, he himself once visited the Rodriguez Orejuela brothers at a Cali hide-out to pass on a request from Mr Botero for $2.5m for the campaign.
The cash was later handed over to Mr Medina in gift-wrapped cardboard boxes by the journalist Alberto Giraldo or then Senator Eduardo Mestre of Mr Samper's Liberal Party, the former campaign treasurer said. Both Mr Giraldo and Mr Mestre are in detention facing charges of illegal ties with druglords.
Copies of Mr Medina's testimony were mysteriously stolen from the prosecutor- general's office last weekend. To the astonishment of journalists at his resignation press conference, Mr Botero quoted from the stolen documents in order to refute Mr Medina's charges. Asked where he had obtained the information, Mr Botero looked distinctly ruffled before saying someone had sent them to him anonymously in the mail.
US and most other diplomats in Bogota doubt whether Mr Samper can survive the scandal. Supporters of last year's conservative presidential candidate, Andres Pastrana, described Mr Samper's government as illegal, saying the alleged cocaine money may have tipped the balance in his narrow victory last year.
Although US officials publicly congratulated Mr Samper and Mr Botero for catching five of the seven Cali cartel leaders recently, some were privately suspicious. "When we put pressure on them, they suddenly came up with results," said one. "When Gilberto [Rodriguez Orejuela] was arrested, he had three guns, one in his belt, and yet no shots were fired. It's highly possible the cartel bosses struck a deal."