Late on Tuesday evening, the family of Muniraj, who died a day after he was hit by a speeding car, was asked by the Egmore police to sign certain documents — the contents of which were not revealed to them.

Chandra, Muniraj’s grandmother, said the policemen told her to come to the station and sign some papers. “They threatened me. So, I packed all my belongings and returned home to Chintadripet,” she said. Meanwhile, the city police issued a lookout notice to airports to prevent 38-year old Shaji Purushothaman, the prime suspect in the case, from fleeing the country.

The police said Shaji was driving the Mercedes-Benz that ploughed into a family sleeping near a footpath in Egmore.

The police arrested 43-year old ‘Kudirai’ Kumar, said to be the driver of the car, on the day of the accident itself. Shaji, however, has been absconding since the accident last Thursday. The police have formed four special teams to go to different States and carry out investigation. “Our counterparts in other States have promised to help us nab Shaji. We are also tracking his cellphone,” said a senior police officer.

The cops have also lifted fingerprints from the car. “We have sent it for testing and hope to get the results soon,” said the officer. The cops have also written to Mercedes-Benz for information on the car’s speed limit.

“We have asked for details on speeding pertaining to the vehicle involved in the accident. We have to gauge the impact of a hit at different speeds,” said the officer.

The cops have also sent Shaji’s photographs to airports in the State to ensure he does not flee the country.

This is probably the first time the police is treating a drunken driving-speeding accident as a major murder case, an expert said.