Nazimuddin Babu, a close associate of Pichchi Hannan, was arrested in the city's Sepoybagh area Thursday evening.
Acting on a tip-off, a team of Rab-3 raided a house in the area at around 6:00pm and arrested Babu, Dhanmondi unit president of Bangladesh Chhatra League (BCL). He was wanted in a number of murder, extortion and kidnapping cases.
On Babu's confessional statement, the elite force arrested one of his associates, Rumi, in the city's Kathalbagan area. In another drive, the law enforcer recovered a pistol from the house of his another associate, Swapan, at Dhanmondi.
At RAB-3 office, Babu told journalists that he along with his cohorts killed at least six people, including Dhaka College student leader Pinto and notorious criminal Shikander, as a sequel to inter-party conflict during the rule of the Awami League.
Babu also confessed to setting fire to some buses during the August 20-22 student unrest.