A Queens woman is undergoing a psychiatric evaluation after throwing a 2-year-old boy off a balcony in Flushing on Tuesday night.

The child was pronounced dead at an area hospital. Authorities say it appears the woman was not related to the boy, but she and her daughter had been sharing an apartment with his family.

Police say the woman has a prior psychiatric history and is currently at Queens General Hospital. She is under arrest and is expected to face murder charges, though Brooklyn prosecutors says the 53-year-old woman must first be deemed mentally fit.