The fatal accident occurred at Vatika flyover on Delhi-Jaipur highway at 10 p.m. on Friday.
The deceased, identified as Sarfaraj Alam (40), Dhirendra Kumar (27) and Satya Prakash Maurya, residents of Bihar, Haryana and Uttar Pradesh, respectively, died on the spot.
The driver of the auto, yet to be indentified, also died in the accident. Besides, another passenger identified as Paranvir Singh of Rajasthan, was critically injured and is battling for his life in hospital.
Sajjan Singh, sub-inspector of Kherki Daula police station said: "The victims were employed in different companies in IMT Manesar. They had boarded a shared auto from IMT Manesar Chowk for Rajiv Chowk. Three of the deceased were sitting on the rear seat while Paranvir was in the middle of the seat."
"Due to lesser traffic at night, all the three vehicles were moving at high speed. The driver of the mini truck suddenly applied brakes and the auto driver also did the same to avoid an accident but the dumper truck coming at a high speed failed to apply brakes on time," Singh said.
"The dumper truck hit the auto from behind and the impact was such that the latter crashed into the mini truck. The dumper dragged both the vehicles for at least 50 metres leaving the auto completely mangled," Singh said.
"We recovered the bodies of the victims from the mangled auto. Paranvir was breathing when the rescue team reached the spot. Till then drivers and cleaners of both the dumper truck and the mini truck ran away from there," he said.
An FIR has been registered for rash and negligent driving at Kherki Daula police station and efforts are on to nab the culprits.
( With inputs from IANS )