New Delhi, Sep 4 (IANS) A day after Faridabad Police found four members of a family dead inside their car, automobile experts Monday said only a detailed investigation of the vehicle would establish whether the deaths were caused by carbon monoxide suffocation.

"There has been no case study of such an accident in the country and I think the police should carry out detailed investigation before jumping to a conclusion," said T.K. Malhotra, president, Automobile Association of Upper India (AAUI).

The bizarre case took place in Faridabad, a satellite town close to Delhi, Saturday evening when the four, including two children, were trapped inside the car. Police believe the deaths occurred because the car was filled with carbon monoxide and the family was suffocated.

Malhotra said the police belief is on the basis of the post mortem reports but no investigation has been carried out on the vehicle.

"I think what the police has explained is on the basis of common thoughts because such an incident does not happen in a few seconds but takes time," said Malhotra, who has been in the industry for the past 26 years.

"The car manufacturers have also not issued any precautionary notice in the manuals which suggests that a deeper investigation is needed in such accidents," said Malhotra.

Meanwhile, Faridabad Police said though they have seized the vehicle, its investigation was yet to begin.

"We are not carrying out any investigation of the vehicle but if necessary, measures will be taken at a later stage," said Mahendra Sheoran, superintendent of police, Faridabad.

He added the investigations have so far revealed that the family died due to suffocation.

Terming the accident as an "unlawful murder" another expert in the industry Rohit Balujja, president of the Institute of Road Traffic Education, said since there have been not many accidents of this nature, the police should carry out a scientific investigation."

According to Balujja, the car should be preserved and sent for detailed investigations.

"Investigators should find out whether the accident was due to a manufacturing defect or faulty servicing by the car dealers."