The activists' led by PYC president Vikramjit Singh Chaudhary protested outside the office of SSP Tarn Taran demanding immediate removal of DIG P S Umranangal.
On May 8, block president Sukhraj Singh was shot dead allegedly by four Akali supporters at Patti Assembly constituency. Two of them were nabbed by police so far.
Umranangal had said the main accused Sarwan Singh was not present at the shooting site.
The DIG's presence will hamper free investigation of the case, Chaudhary said.