The body of Monica, 19, was found under mysterious circumstances by some students when they went to the terrace of the Chhotu Ram polytechnic in Rohtak town, 70 km from New Delhi, police said.
Police said the girl was suspected to have been blackmailed by male friend.
A bottle of insecticide was also found near the body of Monica who belonged to Baliana village in Rohtak district, police said.
Police said that the girl, who had been missing from her house since Sep 20 after she went to attend her computer classes, is believed to have committed suicide as she was being blackmailed by a male friend who had taken her objectionable photos and made her videos.
"This person had asked her to pay Rs.5 lakh and threatened to upload here photos and videos on the internet if she failed to do so. She seems to have taken the extreme step due to this pressure," a police officer said.
The victim's father told police that a suicide note was found in her bag which she had left at home in which she mentioned about the alleged blackmail. He said that cash and jewellery had gone missing from his house in recent months.