The woman was rescued from east Delhi's Dilshad Garden area Wednesday night in an unconscious condition, police said.
"She told us four of her office colleagues took her in a car Wednesday night. On the way, they offered her a cold drink laced with a sedative. When she became drowsy, two of them raped her at a secluded place," said a police officer.
The woman, who lives in east Delhi's Madhu Vihar area, told police that accused Ravindra and Lokendra raped her while Rakesh and Jai Singh were with them.
A case was registered after the victim's medical report confirmed gangrape.
All the accused, who are missing and on the run, work with the victim at a private company in Uttar Pradesh's Gautam Buddha Nagar.