During the course of probe, the police found that prime suspect Sunil alias Sulli had killed wrestler Rajesh Yadav, also his cousin brother, outside Tau Dev Lal Stadium near Rajiv Chowk on Sunday.
The accused then shot dead his wife Vinika Yadav (32), whose body was found in an abandoned Hyundai Santro in Rajendra Park, on Monday.
The suspect shot the duo following Vinika's alleged illicit affair with the deceased wrestler's brother, Ravi, the police said adding that the suspect had used the same revolver to kill both the victims.
A senior police official alleged, "Vinika belonged to Kirij village (Sohna) and was staying at her parent's house from the last few months. She had an extra-marital affair with Ravi, brother of the deceased wrestler. The suspect had been urging her to return and had also apologised for his behaviour. However, he shot her on Sunday evening."
A case of murder was subsequently registered against four persons, including suspect Sunil on Monday. The police had zeroed in on him on Thursday but he managed to flee the city the following day.