Punjab Police on Wednesday arrested four people including a police officer following an encounter in connection with a firing incident in Punjab's Tarn Taran, officials said on Wednesday. The arrested were identified as Yadwinder Singh and Kuldeep Singh, both residents of Ruriwala; Prabhdeep Singh, who hails from Hun Dhai Wala; and Pawandeep Singh, a resident of Sarhali Kalan.