The youth identified as Abhimanyu was on the run while his accomplice, a juvenile, was arrested on November 30, said DCP (northwest) Vijay Singh.
"A team was sent to his (Abhimanyu's) ancestral house in Pratapgarh, UP, which conducted several raids in his village and quizzed his relatives... He was apprehended from the place near his in-laws house. On sustained interrogation, he admitted his involvement in the crime," said the officer.
"They found the woman sleeping and allegedly used chloroform to make her unconscious, while they allegedly raped her. The woman suddenly gained consciousness and resisted the assault, due to which one of the accused allegedly strangled her to death.
"Once they realised that the woman was dead, they lifted her body and put it in a mini-truck in which they had come. They drove to a forested area around 2 km away from the woman's residence and dumped the body there. The duo again sexually assaulted the body there and fled from the spot," the probe agency said.
Even when the neighbours could not trace her, they informed her relatives in Delhi, said a senior police officer. Later, a missing complaint was registered.
It was in the evening that some locals found her semi-naked body and raised an alarm. The mini-truck used in the crime and the woman's mobile phone have been recovered, police had said.