A Roman Catholic nun who advocated for the rights of India's tribal people has been brutally killed in her home in eastern India.

Sister Valsa John had been helping tribal groups who were displaced by coal mining companies in Jharkhand state.

Her brother says she had received threats from local coal mine owners. He told reporters that a group of 50 people barged into her house late Tuesday in the Pakur district and killed her.

Police have not yet made any arrests in connection with her murder.

India's mining sector has been plagued by allegations of corruption. Rights activists fighting on behalf of displaced villagers have called for impoverished communities to get a share of mining companies' profits. The government recently put forth such a proposal.