The deceased Puja was allegedly shot by her husband Mukesh at their residence in double-storey Modinagar area, SP Jagdish Sharma said.
Mukesh has been absconding since the incident came to light.
Acting on a complaint filed by the deceased's father, who named Mukesh and his parents' alleged involvement in the incident, the police is investigating the matter.
According to sources, Mukesh had sent an SMS to his mother-in-law alleging that Puja had illicit relations with another man living in the same neighbourhood and he had problems with it.