A 17-year-old school student, who is an IIT aspirant, allegedly killed the 68-year-old retired teacher who was found murdered in his Vasant Kunj flat two days ago, the police said on Tuesday.
The boy had previously lived as a paying guest at DK Joshi's house. Joshi had thrown him out in March after he caught the boy stealing his jewellery, liquor and credit cards, the police said.
The officers used Facebook to trace the accused to his uncle's house in Gurgaon.
"We knew the names of the boys who had lived as Joshi's tenants. But we didn't have their addresses. We did an extensive search on Facebook and got their personal details," said DCP (south) HGS Dhaliwal.
Explaining how and why the crime was committed, Dhaliwal said: "When Joshi discovered that the juvenile had stolen from him and bought stuff worth Rs 1.3 lakh on his credit cards, he confronted him and made his parents pay for the losses. The boy nursed a grudge against Joshi. On December 16, he came from his native place in Madhya Pradesh, prepared to kill Joshi. He had a dagger and went to the house wearing a wig, borrowed from a friend who worked at a beauty parlour," the officer added.
The police said he also took a friend along.
"He made the friend wait outside. Joshi was not home, so the boy waited. When the old man came in, he attacked him with the dagger. He even stabbed him in the neck with a pair of scissors lying on the table," said another officer.
After the murder, police claimed the boy took off with Joshi's laptop, credit cards and liquor bottles.