The accused identified as Constable Manoj Kumar, is posted with the Special Operations Group of Crime Branch.
Police said that the incident took place when the victim was alone at home as her husband had gone to his village in Jhajjar, Haryana.
Kumar was reportedly drunk when he visited her house on that fateful night and allegdly rape her at gunpoint.
“He came in, shut the door behind him and told me he had just committed a murder and was carrying a gun. He threatened me, saying he would not hesitate to shoot me if I did not do as told," the woman said in her complaint.
Her husband was informed about the incident when he returned home on Wednesday evening.
A case has been registered against Kumar at the Dwarka police station after the medical examination confirmed sexual assault, following which a search operation has been issued to trace the absconding constable.
Officer said that disciplinary action will be taken against guilty constable.
The accused befriended the couple who have been staying in Najafgarh for two years and was regular visitor to their home.