The knife used by the attacker was recovered from the spot, they said.
As Kaur was near to her aunt's house, the suspect who was following her, accosted her. He stabbed her once in the arm and then in the chest. She was rushed to a nearby hospital where she was declared brought dead, said police.
Police haven't ruled out involvement of more than one person in the murder
"A CCTV camera installed in the street shows a scooter first coming into the frame and then taking a U-turn, and then appears Simranjeet and a suspect who follows her. The actual stabbing takes place out of the camera's frame but people running to save her after she is stabbed is recorded in the CCTV," said a police official.
"Although, only one man is seen following the victim, the possibility of more people being involved in the case cannot be denied. It is possible that the man seen on the scooter had been there to do recce," he said. "It is an unfortunate incident. We have registered a case and taken up investigation. We are sure of working out the case soon," said Delhi Police Commissioner B S Bassi.
Kaur's laptop was there with her, police is keeping open both the murder and robbery angle open in the case and thoroughly probing all the possibilities. Investigators have also checked the CCTV footage of the metro stations whether she was being followed from Noida or somewhere midway. Kaur had married more than a year ago and was reportedly pregnant. Her husband too works in Noida in an MNC. They lived in Nanakpura area.