The body of 48-year-old Ram Prakash was found near a makeshift shelter used by the society presswallah. The Amar Colony police said it appeared that head injury caused by a blunt object killed the guard.

A resident informed the police around 9 am that Ram Prakash was lying unconscious. “When our team reached Mount Kailash Apartments, he was already dead,” said an officer.

The body has been sent to the All India Institute of Medical Sciences for postmortem. “Barring injuries on the head, there are no visible injuries on the body. Only the postmortem report can tell us the exact cause of death,” said a senior police officer.

Working for the south Delhi-based Lalit Security firm since November last year, Prakash joined duty at the Mount Kailash Apartments only a month ago. Earlier, he had worked at Savitri Cinema for a month.

A father of five — three daughters and two sons — Prakash was living in Okhla Phase-III with his cousin Gyan Singh. His family is in Phuff village in Madhya Pradesh.

The police are questioning Gyan Singh and other security guards posted at the building. Society residents said they did not hear any noise at night.

The deceased’s neighbours in Okhla are also being questioned.

The police are meanwhile waiting for his family to come to Delhi who can throw some light on his life. His cousin has told the police that Prakash had no enmity with anyone.

The police are also investigating whether a robbery attempt led to the murder. “It is too early to state the motive. We are investigating the case from all angles,” said a senior officer.