(CNN) Concerns about caste-based violence in India are growing after a 13-year-old girl from a lower caste was beheaded in one of the country's southern states last week, with her alleged assailant coming from a higher, majority caste, according to police.

The complaint filed with police in the Salem district of Tamil Nadu alleges that the victim had rejected the advances of the accused, triggering a violent reaction.

"The girl was brutally murdered. The investigation is ongoing and the accused has been arrested," said Ponkarthik Kumar, senior police official in the district.

The police have charged him under the act that criminalizes caste-based violence. The law has existed in India since 1989.

The lower castes, also known as Dalits, one of the most marginalized groups in India's complicated caste system -- a community of people once known as the untouchables, who were often denied the right to education and employment through systemic discrimination and abuse.

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