The 24-year-old mother of a Brooklyn toddler found unconscious in a bathtub over the weekend has been arrested in her death, authorities said.

The death of Melody Pheng, 2, was ruled a homicide, police reported Tuesday. Police had been interviewing her parents since Monday, according to media reports, and later charged the mother.

Lin Li has been charged with second-degree murder, manslaughter and act in a manner injurious to a child, police said.

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Pheng was pronounced dead Sunday night at a hospital after she was found unresponsive around 8:30 p.m. in a bathtub at her Sunset Park home, according to authorities.

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Officials told Pix11 New York that a 4-year-old boy was also found in the house, and was being checked for any potential signs of abuse.

Pheng's 30-year-old father, who was also interviewed by police, is not expected to face any charges, according to ABC7 New York.