The forest officials are tight-lipped on the progress of their investigation.

The elephant's habitat was in the Silent Valley National Park in Palakkad district.

The local Manarakadu police station on Wednesday registered a case in the gruesome incident.

"The forest department and the police are probing the incident and we are confident of finding the villains behind this crime," said Sub Inspector of Police T.K. Ramachandran.

According to veterinarians who treated the 15-year-old pregnant elephant, some miscreants while chasing away the elephants who occasionally stray into the agricultural land had kept fire crackers inside a pineapple.

When the elephant started eating it, the crackers burst, seriously injuring its upper and lower jaw and tongue.

The injured elephant, according to forest officials, was first spotted by locals near a water source on May 23. Two days later an elephant expert after a medical assessment said things were bad for the animal.

On May 25, the elephant was found dead in slushy water.

"Despite our best efforts to get the elephant out of water, it did not come out and died," said a local villager.

A post-mortem conducted on the elephant two days later reveled that the elephant was two-month pregnant. Experts pointed out that this was the elephant's first pregnancy.

On Thursday, Minister of Environment, Forest and Climate Change Prakash Javadekar took to twitter to show his displeasure. "The government has taken a very serious note of the killing of an elephant in Mallapuram, #Kerala. We will not leave any stone unturned to investigate it properly and nab the culprit(s). This is not Indian culture to feed fire crackers and kill," he wrote.

On Wednesday, the Environment Minister sought a report on the death of the elephant and said stern action would be taken against the culprits.