Colombia's foreign minister resigned today shortly after her senator brother was arrested on suspicion he helped finance illegal paramilitaries.
"I am leaving," Maria Consuelo Araujo said. "I see clearly that the judicial process must be free of any interference."
Police arrested the minister's brother, Senator Alvaro Araujo, on Thursday on suspicion he had supported paramilitary leaders who are accused of killing thousands during a dirty war to counter Latin America's long-running rebel insurgency.
Ms Araujo stepped down three weeks before President Bush was scheduled to arrive in Colombia in a show of support for President Alvaro Uribe, who has received millions in US aid to fight drug traffickers and leftist guerrillas.
Arrest warrants have been issued for at least nine pro-Uribe congressmen since late last year when the scandal first broke, and one active army colonel has been suspended from his command while he is probed for paramilitary links.
More than 31,000 right-wing militia fighters have demobilised under a peace deal with Mr Uribe's government.
But human rights groups say powerful paramilitary bosses have been allowed to keep their criminal networks intact.