A North Carolina mother has been charged with the deaths of her 4-year-old twin sons on Saturday.

The Cherokee County Sheriff’s Office said the twins’ father reported them dead when he arrived at his estranged wife’s home to pick them up for custody.

Later that day, the estranged wife, identified as Genevieve Springer, was arrested in Union County, Georgia, where she was briefly hospitalized for an unknown ailment. Upon release from the hospital on Sunday, she waived extradition and was brought back to North Carolina.

Investigators are working to compile a timeline. The boys’ father said he last saw them on February 26. Deputies say they hope autopsies will narrow down the time of the deaths.

No further information was released.

Springer is charged with two counts of first degree murder and is being held without bond.

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[Featured image: Genevieve Springer/Cherokee County Sheriff’s Office]