Dharmendra Kumar alias Veeru was arrested from Sangam Vihar, where he had gone to meet a relative, after police traced him through electronic surveillance of his mobile, a senior police official said.
"He had developed illicit relation with the wife of Vidya Nath (35) and when HE came to know about it, Kumar killed him with a screwdriver," A K Ojha, Additional CP (southwest) said.
The victim's body was found in a pool of blood at his house in Bharat Nagar in southwest Delhi. Though his wife informed police about the incident she denied Kumar's role.
During investigation it was found that Kumar, a distant relative of Nath's wife, was also living in the same house.
"Suspicion was raised when he tried to evade probe by claiming that he was not in town. Later his location was traced through his call records in west Delhi," Ojha said.
During interrogation, he said that Nath was demanding money from him, and on the fateful day when he again asked for money, he killed him in a fit of rage, the official said, adding further investigations were on.