A district-level leader of Bangladesh Nationalist Party (BNP) was died in Gaibandha jail custody.The deceased is Gausul Azam Dolar, General Secretary of Gaibandha BNP and son of Md. Aftab Khandakar, of Poschimpara area of Gaibandha municipality.Police claimed that he was suffering from cardiac problems and died on Saturday at 8.30am.Confirming the matter, Md. Masudar Rahman, Police Superintendent of jail, said, Dolar was died during his treatment at Gaibandha Sadar Hospital.It is mentionable that, police arrested Dolar in sabotage case from Matherbazar area of Polashbari upazila in Gaibandha on October 5.