"Prima facie it appears that the tortoises died following leakage of some chemical in the lake. Their carcasses have been sent for post mortem," District Forest Officer S P Parmar said.
"An inquiry has been ordered into the incident. The reason behind their death will be known in the post mortem report," he said.
The Lakhota lake, is under control of the municipal corporation and security guards have been deputed to maintain vigil, forest department official said.
"It is surprising that so many tortoises have died in the lake at a time when vigil is being maintained by the security guards here," he said.
Efforts are underway to rescue the remaining tortoises in the lake, an official said.
Published 29 March 2011, 11:35 IST