The viscera of the 100 monkeys found dead over the past few days in Amroha district have been dispatched to the Indian Veterinary Research Institute (IVRI) in Bareilly and the report is awaited, an official said on Friday.
The deaths of the simians has triggered outrage among environmentalists after which the state government swung into action.
A team of veterinary doctors has already conducted an autopsy on the dead monkeys but it was not able to infer conclusively the cause of death, after which the viscera were sent to Bareilly, the official told IANS.
The district authorities have also initiated a police investigation after some residents raised doubts that the simians might have been poisoned by some locals whose crops were damaged by them.
The villagers in their interactions with the police have said that most of the monkeys passed blood-stained stool and vomited before they died. On an average, a dozen monkeys have died over the past one week.
Tejpal Singh, a doctor who conducted the post-mortem on the monkeys, has told officials that many organs like the liver and the lungs of the animals were badly damaged and their stomach was empty.