Church leaders in Kerala, India have expressed shock and outrage over the killing this week of tribal rights campaigner Sister Valsa John.

The 53-year-old nun from the Sisters of Charity of Jesus and Mary was hacked to death at her home in the remote Pakur district of the east Indian state of Jharkhand, according to UCANews.

According to reports, a mob of around 50 people gathered outside her home in the early hours of Wednesday morning (local time) shortly before her death. Earlier reports had said the nun had been shot dead.

UCA News says Major Archbishop and head of the Syro-Malabar Church, George Alencherry, and Curia Bishop Bosco Puthur yesterday visited Sr John's family in Vazhakala, near Kochi, Kerala's commercial hub.

After offering his condolences the Major Archbishop paid tribute to the slain nun, the website said.

Major Archbishop said Sister Valsa John had "given her life to the poor and fought a long battle to try and safeguard their rights. She had shown the world how to care for the poor and dedicated her life to the Church and her faith." He also called for those responsible for her death to be brought to justice.

Sr. John's brother, M. J. Baby said he had warned her not to return to Jharkhand when she came home for a holiday at the end of August.

"I told her not to go back after she told me about threats she had received," he said.

UCA News says the family believe the nun was killed by people connected to a mining company she was campaigning against.

Offering his praise to the dead nun, Kerala regional Latin Catholic Council president, Archbishop Maria Calist Soosapakiam said: "With her exemplary life and courage to fight evil, Sr John has shown us that we need to rededicate our lives for our faith and work for the poor."

Earlier reports said the 53-year-old nun from Kerala who led campaigns to defend tribal rights was shot dead Nov.15 in the eastern Indian state of Jharkhand.

Sister Valsa John, who belonged to the Sisters of Charity of Jesus and Mary, was killed during an alleged encounter near her home in the early hours of Tuesday morning in Pakur district, near the city of Dumka.

Bishop Julius Marandi of Dumka said Wednesday the circumstances surrounding her death are not yet clear.

According to Sister Lilly Mary, the dead nun's congregation provincial, Sister John was working with people belonging to the Santhal tribe and was living alone.

She had been protesting against mining corporations that were exploiting the tribal people of the region, she said.

UCA News said the nun, who hailed from Eranakulam in Kerala, was arrested in 2007 for protesting against a coal mine on tribal land that had allegedly been acquired illegally in Jharkhand's Pakur district.

The provincial, however, said that case had been settled.

The Catholic bishops' conference spokesman, Father Babu Joseph, said the local church will demand a thorough investigation into the tragedy by the state government.

Sister John's funeral was scheduled for Thursday, he added.