Five rare Asiatic lions were killed by an electrified fence on the edge of western India's Gir National Park. The fence was placed there illegally by a farmer near wildlife area, said chief wildlife warden, Pradeep Khanna.
"The carcasses bore the marks of electrocution," Khanna said.
Such lions once roamed much of Asia, but only about 350 are known to remain _ all in Gujarat. The Wildlife Protection Society of India says their bones are all highly prized in traditional Chinese medicine, as are their claws, which are sometimes used for amulets in India.
Khanna said police have arrested the farmer, who faces seven years in prison if convicted of building an unauthorized fence that killed the animals.
The lions often wander outside park boundaries to seek food and water, and get caught in poachers' traps.
A statement from the Wildlife Protection Society of India said the latest deaths took to 32 the number of the park's Asiatic lions that have died this year. It was not immediately clear how many were reported dead last year.
Poachers killed eight, electrified fences killed six, five died after falling into open wells, one was hit by a vehicle and 12 were found dead of unknown causes, the statement said.
Khanna declined to confirm the claims by the society, which said fences pose a serious threat to the rare animals.
"The Asiatic lion is one of the most critically endangered species on this planet, and this added twist of so many lions being killed by electrocution from crop protection fencing is a catastrophe," said Belinda Wright, Executive Director of the Wildlife Protection Society of India.
In April, the state government announced plans to improve security at the sanctuary. It allocated US$9 million (Ђ6.3 million) to protect the lions with more guards and advanced security equipment, including closed-circuit video cameras.
The sanctuary is nearly 185 kilometers (115 miles) south of Ahmadabad, the main city in western Gujarat state.