Police on Thursday recovered blood-stained clothes and an army knife allegedly used in a triple familicide in south Delhi's Neb Sarai area from a nearby forest.

Twenty-year-old Arjun Tanwar was arrested on Wednesday for allegedly murdering his parents and sister.

Ex-armyman Rajesh Kumar (51), his wife Komal (46) and their daughter Kavita (23) were found dead at their house in Deoli village on Wednesday morning.

According to the police, Tanwar did not have good relations with his parents and was upset that they liked his sister more than him.

The police recovered his blood-stained sweatshirt and the army knife which he used for killing his parents and sister from Sanjay Van late Wednesday night.

During interrogation, Tanwar told the police that he first killed his sister by slitting her throat while she was asleep.

Then he went upstairs where he stabbed his father in his neck and slit his mother's throat, who was in the washroom, police said.

Tanwar then changed his blood-stained clothes, put them in his gym bag and went to Sanjay Van where he dumped them along with the knife used to commit the crime, they added.

After coming back home, he tried to clean blood spots in the washroom and other articles in the house, the official said.

Tanwar then provided a false alibi to the police, claiming he had been at the gym when the family members were murdered, he said.

The accused was pursuing a degree in political science at a Delhi University college and was a trained boxer. He represented Delhi in a state boxing event, where he won the silver medal. He had previously studied at the Army Public School in Dhaula Kuan.

Except for the headline, this story has not been edited by The Telegraph Online staff and has been published from a syndicated feed.