Hundreds of crows and fishes have now been found dead in the Ana Sagar Lake in Ajmer since the past three days.
The forest department buried around 30 crows in the Ghooghra nursery in Ajmer and were awaiting the viscera report from Bhopal to find out the cause of the death.
Officials confirmed that crows found in and around the Ana Sagar lake appeared feeble and inactive and hence it is feared that the death toll might increase.
Also, over 100 fish were found dead in the lake on Saturday.
Officials said pollution and lack of oxygen in the lake was the reason for the death of fish.
During winters the Ana Sagar lake attracts thousands of migratory birds.
The locals have accused the forest department and animal husbandry department of initially hiding the reports about the death of crows.
Prima facie officials said that there were chances of crows dying due to some poisonous food. But, the question was who could have spread the food around the lake and this needed to be investigated, they said.