(CNN) A woman has been arrested in Phoenix on suspicion of killing her three children -- her infant daughter, her 2-year-old daughter and her 3-year-old son -- police said Tuesday.

Police found Rachel Henry's children dead in their Phoenix home Monday evening after someone there called 911 to report some kind of unspecified trouble, police Sgt. Mercedes Fortune said.

"The ... mother has admitted to harming her three children," leading to their deaths, Fortune said.

Henry, a 22-year-old who recently moved to Arizona from Oklahoma, is being held on three counts of first-degree murder, Fortune said.

UPDATE: Mom arrested, admits to killing kids ages 3, 2 and 7 months. Mom is a 22-year-old woman who recently moved to Arizona from Oklahoma. Crime happened in their home near 24th Street and Vineyard pic.twitter.com/iqCivZ66jZ — Phoenix Police Department (@phoenixpolice) January 21, 2020

Fortune did not say how the children died, or how Henry allegedly harmed them.

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