New Delhi: Nitin Verma, who allegedly killed his pregnant young wife and their parents at their southwest Delhi home, was arrested by police on Saturday night.

"He has confessed to the crime and also the fact that he was having an extra marital affair with a girl, which drove him to the extreme step. We are probing the matter further," police officer Shalini Singh said.

Nitin reportedly had an affair with two women before his marriage. While he married one of them, he wanted to continue his "close relationship" with the other too, the police said.

"Nitin had achieved one thing in life - marrying Pooja - but he wanted more", Singh said.

"Despite marrying his love Pooja, he also wanted to continue his relationship with the other close friend".

Singh said that since Pooja did not approve of his close relationship with another girl, Nitin got frustrated and finally took the extreme step of killing her.

Pooja, 24, was two months pregnant and worked as a teacher at a private school. They were married on January 24, 2007.

Stab wounds

Pooja and Nitin's parents were found dead in their house in Rajnagar locality, near Dwarka late Friday night with multiple stab wounds. Nitin, the police said, had planned to kill Pooja, but was caught in the act by his parents. When they tried to stop him, he attacked them also.

The bodies were discovered by a neighbour alerted by Pooja's uncle Vijay.

On being informed, Vijay rushed to the house.

With no valuables missing and no forced entry, Nitin's contradictory statements made him the prime suspect.