The three men were found inside a Honda City car around 7.15 p.m. Monday in Laxmi Bai colony near INA market in south Delhi. A local resident spotted the car and called up the police.
The three have been identified as Lakshman, Balvinder and Nishant Datta. All are in their mid-20s, a police official said.
They were into event management and were to make a payment of around Rs.1.5 lakh. But the money was not found in the car, a relative of Nishant said.
He said that they were found unconscious and frothing from the mouth. They had also vomited in the car.
He quoted the police as saying that the car windows were rolled up and the airconditioning was on. So, the investigators are looking at the possibility of the deaths being caused by carbon monoxide poisoning since there were no signs of any struggle in the car.