New Delhi, Dec 19 (IANS): Driven by his greed for a new mobile phone, a 17-year-old from a slum took a man to an isolated spot after promising gay sex where he battered him to death with a stone.

He then disappeared with the 35-year-old dead man's telephone, leaving a perplexed Delhi Police hunting for clues to get to the killer.

The gory incident took place Sep 24 in a largely isolated park near the Adilabad fort in Tughlakabad area in south Delhi.

The victim, Guddu, and the killer had met only hours earlier on a bus, police said Thursday. The victim, a cab driver, asked the teenager if he would agree to have sex.

The boy told police that he agreed to the deal so that he could rob the man of his gleaming mobile.

After the murder, he escaped with the phone but got only Rs.50 from the victim's purse.

When police found Guddu, he was half naked. His face had been smashed with a huge stone, which lay nearby.

For weeks, police remained in the dark.

One day, a group of boys in the fort complex told police that a teenager who used to play "gulli danda" with them had not been seen since the day of the murder.

On Wednesday, a police team sprang on the young killer at his home in Sangam Vihar in south Delhi.

Deputy Commissioner of Police P. Karunakaran said the juvenile knew the topography of the Adilabad fort well.

"The juvenile kept the mobile phone in his house but did not use it as he was aware he could be caught by police," said Karunakaran.

The killer has been sent to a juvenile reformation home.