MADHUKHALI (Faridpur) : Madhukhali Upazila Teacher and Staff Welfare Association forms a human chain at Dhaka-Khulna Highway protesting killing of Haji Yunus Ali School and College teacher Utpal Kumar Sarkar of Ashulia, Dhaka and assault of Mirzapur United Degree College Principal Swapan Kumar Biswas of Narail recently.