A prisoner who was arrested during a joint forces’ operation in Keshabpur upazila of Jessore  district on Thursday died at Jessore  Central Jail hospital on Friday.

The deceased was identified as Ujjal Biswas, 39, son of Najir Biswas of Altapole in Keshabpur upazila, reports UNB.

Abid Ahmed, Jailer of Jessore  Central Jail, said when Ujjal was sent to Jessore  Central Jail around 9 pm on Friday, he fell unwell as he had been subjected to a mob assault.

Later, he was shifted to Jail hospital and around 10:30 pm, Ujjal’s condition deteriorated further. He was pronounced dead while undergoing treatment at Jessore  General Hospital around 10:45 pm.

The body bore several injury marks, he said.

During a joint forces operation, law enforcers arrested four people, including Ujjal, along with arms, sharp weapons and drugs on Thursday night from Keshabpur upazila, said police.

Three separate cases were filed in this connection.