Of the arrested, Rakibur Rahman alias-Rocky 18, son of Mohammad Hanif, and Bilal Hossain, 19, son of Solaiman were identified to be the boys' friends. Both are second year students of Islamia College.

Police said Rocky and Bilal on Monday noon called Utpal Basak, 18, Pulak Saha 17, and Sujit Kumar Saha, 18, out of home to see a football match at Dohokhola village in sadar upazila, 15 kilometre off the district headquarter. Utpal and Pulak are second year students of Kushtia Islamia College while Sujit studies at Kushtia Commercial College.

When the three reached the village, some unidentified men picked them into a microbus at about 4:00pm and took them to a secret location, they said.

Later the abductors communicated with the boys' families and demanded TK 15 lakh for release. They warned the families not to file any case.

Meanwhile, police, though informed verbally, were trying to trace the boys.

Police while probing found Rocky and Bilal, who too were missing since the incident, to be involved with the abduction. They picked up Rocky's father Hanif and his maternal uncle Rabbani for quizzing.

Afterwards, an anonymous caller informed the police that the boys had been freed at a hut near Barkhada field in sadar upazila.

Police rushed to the scene and found the boys tied up and blindfolded, said Gius Udin Ahamed, officer-in-charge of Sadar Police Station.

The arrested were being quizzed till filing this report at 7:00pm yesterday.