Ranjit Biswas' body was found by another security guard, who reported for duty in the building on Jogendra Kaviraj Row this morning, a Kolkata police officer said.
The body was lying on its chest inside the lift with the mouth sealed with brown tape and a bedsheet tied around the neck, he said.
His wallet was found lying empty on the fifth floor but his mobile phone could not be located.
The man, a resident of Midnapore, was working for a city-based security agency and had joined as a securityman of the building three and half months ago.
The miscreants put tapes on the CCTVs on the fifth floor of the building to avoid detection, he added.
