The fishermen fishing nearby informed the cops and forest officials shortly after discovering eight monkeys in a dazed position, of which seven died immediately. The carcasses were then taken to the Chengalpattu Veterinary hospital and the lone surviving monkey was rushed to the Mamandur Veterinary hospital for treatment.

The monkeys were found to have consumed spiked food following the post mortem. The forest officials alleged that this could've been the act of people who felt troubled by the monkeys. Case has been booked on those unidentified people under sections 9, 39, 50 and 51 of the Wildlife Protection Act 1972.

Investigations are in a limbo with the CCTV cameras in the vicinity are found to be defunct.