The elephant was a full grown one and was unwell for the past few days.
The animal was hacked to death last night allegedly by poachers who inflicted multiple injuries and bludgeoned its head, forest department sources said.
District Forest Officer Bidyut Sarkar said the incident was the first of its kind in north Bengal and investigation into it would be conducted.
Conservationists in the area have demanded a CID investigation into the incident.