The incident took place here this morning in northeast Delhi's Jahangirpuri area when the security guard, identified as Mansoor Beig, was standing close to the excavation site.
"During a swing of the machine's arm, Beig's head was severed and it fell in the dug out soil while the torso collapsed on the spot. As eyewitnesses screamed in disbelief, the excavator's operator, identified as Naresh Kumar, stopped work and fled the spot," said a senior police officer.