Over five years after Punjabi singer Navjot Singh, also known as Isapuria Virk, was shot dead in Dera Bassi in May 2018, the crime investigation agency of Mohali police has cracked the case with the arrest of one of the killers. The arrested accused is Abhishek, 25, alias Rajat Rana, a native of Shamli district, Uttar Pradesh, who was just …