A prison van carrying an aide of Mufti Hannan, chief of banned militant outfit Harkat-ul-Jihad al-Islami (Huji), came under grenade attack in the College Gate area of Tongi under Gazipur district on Monday.Police detained the attackers with 10-15 crude bombs and Tk 7500, said Gazipur Traffic Police Inspector Md. Hafizul Islam.The detainee was identified as Mostafa Kamal (22), son of Mozammel Hossan, a resident of Pagli village under Tarakanda police station of Mymensingh district.Inspector Hafizul said the prison van was taking back Mufti Hannan’s associate from a Dhaka court to Kashimpur jail. The youth threw two grenades aiming the prison van while it was crossing Tongi college gate at 5:00pm.The bombs were exploded on streets but anyone wasn’t injured, he said.The youth said that he threw the grenades in returns for Tk 10,000, the police added.