An official of the bank was also arrested by the ACC officials.
The detainees are Shahin Shikder, joint convener of Jubo League Barisal town unit, his wife Naima Shikder, and Jakir Hossain, senior executive officer and credit in-charge of United Commercial Bank.
Kotwali police station Officer-in-Charge Shah Md Awlad Hossain said the ACC official handed the trio over on Monday night.
According to ACC sources, a case was filed against the trio on December 19 last year for embezzling Tk31.65 lakh of the bank.
Motiur Rahman, deputy director of Barisal district office, investigated the matter.
The trio were arrested on Monday night after the allegation against them had been found to be true.