The incident occurred in the early hours of Sunday near Veena Enclave here when Sandeep, 30, was headed towards Railway Road from Nangloi police station during duty hours in plainclothes.
While Sandeep was on duty, he met his colleagues, Constables Khushi Ram and Sachin, who were returning home after duty.
"We spotted him (Sandeep) on his bike in plainclothes. I asked him about his duty hours and he told us that on the directions of his SHO (station house officer), he was on duty in plainclothes as incidents of thefts had increased in his beat area," Ram stated in the FIR.
As the three started moving towards Nangloi Railway Road, they saw a white Wagon R parked near a government school and that two men inside it were consuming alcohol, the FIR said.
"We identified one of the occupants as Dharmender alias Bhandre, who lives in Veena Enclave. Since I was previously posted at Nangloi police station, I knew Dharmender," Ram said in the FIR.
When Sandeep objected to the duo drinking alcohol on the road, Dharmender shouted, "You are interfering in our personal matter. How dare you?"
Sandeep asked Dharmender and Rajnish to come to the police station but the two started moving towards Nangloi railway station in their car.
Sandeep chased them on his motorcycle. Ram and Sachin also followed them.
After reaching near Jaat Dharmshala, Dharmender slowed down the vehicle and waited for the three policemen to get close.
As he approached the car, Sandeep asked the accused to stop their vehicle. Instead, Dharmender hit Sandeep's motorcycle with his car.
Dharmendra stopped dragging Sandeep only after his car hit the other car.
While Ram and Sachin rushed to Sandeep's rescue, Dharmender managed to flee the spot, leaving behind the car. Rajnish was nabbed from the spot, the FIR stated.
Ram and Sachin rushed Sandeep to Sonia Hospital. He was then referred to Balaji Action Hospital, where he was declared dead.
Rajnish managed to give the constables a slip while they were running around for Sandeep's treatment at Sonia Hospital. He was caught by police on Monday.
Deputy Commissioner of Police (Outer) Jimmy Chiram said Rajnish was questioned and efforts were being made to nab Dharmender.
A senior police officer said they are also trying to ascertain if the accused have connections with bootleggers in the area. It will be clear once prime accused Dharmender is arrested, he said.
Police said the car used by the two accused did not belong to any of them and the car owner was also being questioned.
A 2018-batch constable, Sandeep was a native of Rohtak in Haryana. He is survived by his mother, wife, and a five-year-old son.
Sandeep's body was handed over to his family members. Senior Delhi Police officials visited his home to pay their last respects.
In a post on X, Delhi Police said it stands with the bereaved family in this difficult time.