To those who met him, gangly and introverted Ravi Singh (25) didn't come across as someone who could turn violent. What is it then that drove a seemingly 'normal' person like him to kill five people within two days at places separated by nearly 70 km?
Experts say emotional attachment to someone or something and then the realisation that it cannot be yours, can sometimes cause pain and a sense of loss that might seem catastrophic and push a person to the brink.
"Ravi was not physically strong and I couldn't have imagined that he would come loaded with guns and kill my nephew Naveen and four others," said Satbhan, Naveen's maternal uncle who lives in Dwarka.
"But he seemed very intense at all times and could have been planning to harm someone without making his feelings apparent," he said. "While no one noticed, Ravi had turned into pure evil."
"Sometimes people who might not have a violent personality start feeling intense rage and enter a very different state of mind when he or she is very emotionally involved with something, which could be a love affair or an important thing in life, and wants it very badly but doesn't get it," said Dr Pulkit Sharma, clinical psychologist, VIMHANS.
"The person can harm himself so that others feel a sense of guilt, he can destroy himself and the person or object he can't have and thirdly, he can turn all the anger into a form of punishment to everyone he thinks is getting in way of what he wants," he said.
"We call such phenomena extended suicide where a person kills not only himself but also others. If a person is introverted and doesn't open up, it is possible that all those feelings are cumulating inside and pushes the person to a point of no return," said Dr Rajesh Sagar, additional professor at psychiatry department, AIIMS.