The retired Colombian striker was taken in by officers in Madrid on Tuesday before undergoing an hours interrogation.
He was allowed to go home after questioning and has since pleaded his innocence.
“I’m very calm,” Congo told sports show El Chiringuito. “It’s not a comfortable situation, but I’m at home… relaxed. They asked me a series of questions and, at the end, I returned home.”
Congo was on Real Madrid’s books for three years having been signed at the start of the Galactico era in 1999.
The forward never actually made his competitive debut for the Los Blancos however, after being shipped out on three separate loan spells before his permanent departure in 2002.
He revealed that he may still have to speak to police again in conjunction with their enquiry.
“They told me to be ready for another call,” he said. “I’m free and I’m relaxed because I don’t traffic cocaine, I don’t have cocaine at home.
“The police said to me that I have to stay away from certain people who are no good for me. That I have to be aware of things and do them in a different way.”
Congo was one of 10 individuals detained by Spain’s Central Narcotics Brigade as part of their operation, according to Marca.
He now works as a pundit for El Chiringuito having moved into the TV studio after hanging up his boots.
Upon signing for Madrid from Once Caldas, Congo became the most-expensive Colombian footballer of all time, costing €5million (around £3.1m).
After stints on loan at Valladolid, Vitoria Guimaraes and Toulouse, Congo was signed by Levante, before representing several other Spanish clubs.
He also earned 17 caps for his country, and featured for Colombia at the 1999 and 2004 Copa America tournaments.
His involvement with Real Madrid in recent years has stretched only to charity performances, though he did score in a benefit match aimed at tackling drug use in 2002.
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