``Prima facie the stone was not pelted by mischief mongers, as the place where the incident took place is inhabited. It is likely that the vibrations caused by the high-speed train gave momentum to gravel laid under the track. Such gravel might have hit Hari,'' acting Superintendent of Railway Police B B Mohite told The Indian Express.

The railway police have already retrieved the stone which hit Hari and it is being sent for chemical analysis to determine whether it was the gravel laid under the track, he added.

Meanwhile, Hari's body was handed over to his relatives after a post-mortem was performed at a hospital in Kurduwadi. A special compartment was attached to the Mumbai-Nagercoil Express last night to carry Hari's body to his village Sanavpatti in Tirunelvellidistrict in Tamil Nadu.

The Railway Police have intensified vigil on board various trains plying at night in the wake of the incident which took place on the night of March 31. A total of 120 armed police personnel have been deployed for the purpose. Normally, a party of four armed police personnel accompany every train plying at night.

Besides, Mohite said, a special squad comprising of three sub-inspectors and 14 constables has been formed to track down those hurling stones at train commuters.

Mohite added that barely four days prior to Hari's death, he had forwarded a letter to the Divisional Railway Manager requesting that wire mesh should be fitted on the windows of trains to ensure commuters' safety.