Radhika Tanwar had been spurning his advances for a long time. But on Tuesday, she paid with her life for not reciprocating the attention of the as yet unidentified man.
Reportedly, Radhika's stalker had been harassing her for a long time. By all accounts, Tuesday's incident was not a crime of passion.
The police believe that the accused followed Radhika, did reconnaissance of the area and chose the spot to kill her, so to make a quick escape.
The south Delhi Police are looking for a youth who was reportedly living in the same locality as Radhika in Naraina village.
According to them, the accused was allegedly harassing and stalking Radhika.
"He was trying to be friends with her but Radhika was not interested. Then he started following and stalking her everywhere she went," said a senior police officer on the condition of anonymity, as he is not authorised to speak to the media.
The police said that it is believed that when her family members got to know about it, they allegedly thrashed him five days ago and told him to stay away from her.
"We are ascertaining all these facts. Right now, our prime suspect is this person who we are on the lookout for," added the officer.
The police said that the assailant planned the murder in detail.
"He followed Radhika from her house to Satya Niketan. When she was on the pedestrian bridge, with her friend, Aditya, the assailant allegedly took out a countrymade pistol and shot her at point blank range," added the officer.
Radhika was hit in the spine and was brought dead to Safdarjung Hospital.
Aditya then gave chase to the killer but he escaped.
The police believe that he had parked his motorcycle on Benito Juarez Marg in advance to make a quick escape.
Even as Radhika's family believes that the accused is a student of Ram Lal Anand College (RLA), the authorities have denied it.
"The killer is an outsider and not from our college," said Vijay Sharma, Principal, RLA morning college.
Commenting on the murder, Delhi CM Sheila Dikshit said she has taken up the case with the police commissioner.
"I have expressed my great concern. I spoke to the police commissioner. We are going into it," she said.
The incident at Satya Niketan took place even as there was maximum security in the area, as President Pratibha Patil was supposed to pass through in a few hours.