Sunil Kumar, (29) of Chamaria village here, was attacked with sticks by the group in the parking lot of the shopping mall in the wee hours today.
Police said they went through the CCTV footage, in which Kumar can be seen coming under unprovoked attack by the group which attack him indiscriminately.
One more security guard who came to his rescue also sustained injuries and was shifted to hospital.
According to the investigating officer in the case Ramphal, the seriously injured victim was rushed to PGIMS hospital here where he died moments later.
Police said that on the complaint of the victim's father and also on the basis of evidence that has come to fore from CCTV footage, a murder case was registered against the accused.
When asked what could be the provocation behind the attack, Ramphal said it was unclear what led to the incident. Police, however, was probing if there was any old enmity between the two sides.