There has been public outrage in India after CCTV footage emerged of a man described as an obsessive stalker launching a frenzied attack on a young woman while bystanders did nothing to intervene.

The woman, a 21-year-old schoolteacher named only as Karuna who was on her way to work at a nearby private school, died in the brutal attack.

In the video, the man, named locally as Surender Singh, 34, is seen holding Karuna back as he stabs her repeatedly with scissors. She falls to the ground where Singh continues his assault, hitting her on the head with a rock and kicking her body.

At one point, a man appears to challenge the assailant but after being warned off he leaves the scene.

Many pedestrians, and drivers, also pause to watch before leaving the area. Singh was finally detained by other locals as he tried to escape and arrested at the scene in the Burari area of the Indian capital at around 9am on Tuesday (20 September).

Police official Esha Pandey told the BBC: "She was attacked as she was walking with her cousin at around 9am. It seems that the assailant started liking her when they used to be neighbours earlier, but since he was married, she never paid attention."

The killing has sparked outrage in India, and many people expressed horror that no-one tried to save Karuna's life. One tweeted: "That is the worst thing I've ever seen. That poor woman had nobody to help her. DISGRACE." Another said: "Its mind numbing how some guys hesitated around for sometime & then fled. They could have saved her! What would I do?"

Two days earlier another woman was killed by an alleged stalker, also in Delhi. On Sunday (18 September) Sanjay Kumar, 26, attacked mother-of-two Laxmi, 28, in Inderpuri before killing himself.

Violence against women in India has sparked public debate recently, particularly since the gang rape and murder of 23-year-old student Jyoti Singh on a Delhi bus in 2012.