The big cat pounced on a man, working in the plantation premises and seriously injured him, following which the animal retreated into the tea bushes, they said.
The garden authorities informed the police and forest department officials but before they could reach the spot, a group of tea garden labourers were again attacked by the animal and four of them got injured in the attack.
The irate labourers then beat the leopard to death.
The leopard carcass was later handed over to forest personnel when they reached the garden, the sources said.