Former Tata Sons chairman Cyrus Mistry and his friend Jahangir Pandole had received multiple injuries and "blunt thorax trauma" in the car accident in which they were killed almost instantly, a medical officer from the J J Hospital here said on Tuesday.

The injuries also included vein ruptures causing internal bleeding, he said.

Mistry (54) and Pandole were on way to Mumbai from Gujarat along with two other persons when their car hit a divider on a bridge over the Surya river in neighbouring Palghar district of Maharashtra, around 100 km from here, on Sunday afternoon.

Mistry and Jahangir Pandole, who were on the back seats, were killed.

Gynaecologist Anahita Pandole (55), who was driving the car, and her husband Darius Pandole (60), who was sitting in the front seat, survived with injuries.

The bodies were later brought to the state-run J J Hospital in Mumbai where doctors conducted the autopsy.

"The impact on the bodies of both Mistry and Pandole was sudden and forceful because of the speed of the car. It led to multiple injuries and blunt thorax trauma, the medical officer said.

The multiple injuries also included rupturing of veins causing internal bleeding. However, the primary autopsy report could only indicate some vague symptoms. A detailed analysis will explain everything and the exact cause of the death, he said.

As a standard procedure, the viscera sample will be sent to a forensic science laboratory in Kalina area here for a detailed analysis, he added.

The deceased were not wearing seat belts as per a preliminary probe, a police official earlier said, adding that over-speeding and an "error of judgement" by the driver caused the accident.

Prima facie, the luxury car was speeding when the accident took place, the official had said.