Three women including a French citizen were killed and nine people injured in the weekend bombing, condemned by Colombian authorities and rebel leaders as a bid to disrupt the country's peace process.
The demobilization of the leftist FARC and peace talks with the last active rebel force, the ELN, are meant to end more than half a century of violence.
Authorities yesterday said the detainees were part of a fringe group called the Revolutionary People's Movement (MRP), which has been blamed for several low-impact attacks in the capital.
No group has claimed responsibility for the mall bombing, which was the second major attack this year in the Colombian capital.
In February, the ELN claimed a bombing at a bullring in Bogota, which killed a police officer and wounded more than 20 people.