Dias, who was in the forefront of protest against some big tourism projects requiring large-scale land acquisition, had gone missing on November 6 last year after he went for a swim at night with two other boys from St Estevem village in North Goa.
His body was found floating in a rivulet near the sluice gate at St Estevem Island the next day.
A section of people reportedly suspected that he was murdered following which the Crime Branch was handed over the investigation into the case by Old Goa Police.
Kashyap said the panel of doctors from Goa Medical College and Hospital have to give the final report detailing cause of the activist's death.
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"The viscera and diatom report do not provide anything supporting the claim of murder. We also don't have circumstantial evidence which states that he was killed. There are no marks on his body," the SP said.
Two separate autopsy reports had earlier ruled out any injuries on the body before the death.
The Central Forensic Science Laboratory (CFSL), Hyderabad had not found any suspicious material in the viscera of Dias.
Dias was last seen with two minor boys, who were earlier questioned by the Crime Branch.