Further action against the SSI would be taken on the basis of the final report, he said.
To a question, the IGP said there was administrative negligence and the DSP was probably unaware about the "quantum of trouble" in the area.
Five policemen had earlier been suspended in connection with the slaying of the DSP.
The DSP was killed in mob violence in Kunda on Saturday when he had rushed there during the course of his duty after a village head was shot dead over a land dispute.