Various media reports have linked Buitrago to veteran drug trafficker and potato wholesaler Marco Antonio Gil Garzon, who was arrested in March on trafficking, money laundering and illicit enrichment charges.
Buitrago retired from the police force that same month. He repeated Monday that his only relationship with Gil was rescuing the man's kidnapped daughter when he was head of Bogota's anti-kidnapping police in the 1990s.
"Innocent, innocent, and I'm going to show it," Buitrago told reporters as he entered the prosecutor's office.
Buitrago was Uribe's security chief in his second term from 2006 to 2010.
Uribe is barred from seeking a third term and is running for Senate in March elections. He said via Twitter on Monday the police and Defense Ministry need to explain why Buitrago was chosen to head his security detail.