The accused are Titu, 20, son of Rustam of Bakra village, and his friends Saju, 21, Yasin, 18, Saju, 21, of Shibandokati village, and Sujon, 21, son of Shajahan of Jekati village in the upazila.
Family members said Titu and Saju gagged the girl and picked up on a motorcycle when she was returning home from a shop around 8pm on February 14.
They took her to a garden behind the Water Management Samabay Samity where Sujon and Saju joined them and violated the girl in turns.
Locals found the girl in a senseless condition and later she got her senses and disclosed the matter to her family.
Victim’s father demanded punishment of the culprits.
Sheikh Shahinur Kabir, officer-in-charge of Bakra Police Investigation Centre, said they did not get any complaint in this connection. Necessary measures will be taken after complaint, the OC added.