A Long Island, N.Y., mother has pleaded guilty to two counts of first-degree murder more than four years after she suffocated her 2-year-old twin daughters.

Tenia Campbell, of Medford, pleaded guilty to the charges on Wednesday and is expected to be sentenced to 20 years to life in prison, according to theSuffolk County District Attorney’s Office.

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Tenia Campbell twin daughters

“This is such a sad and tragic case. Those two little girls looked to this defendant, their mother, for protection and love. Instead, she executed them,” District Attorney Raymond A. Tierney said in a release. “The defendant has one thing those twin girls will never have again: life," he added. “But now, this defendant will get to live out the majority of her life behind bars.”

Campbell’s attorney John Halverson told PEOPLE that Campbell “wanted to put this behind her” and “lives it every day of what her actions were and what she’s done.”

“There was some closure to this,” he said. “Part of her is now able to move forward.”

Tenia Campbell.Facebook

Tenia Campbell twin daughters

As the DA’s office notes, Campbell’s mother first called police at 2:37 p.m. on June 27, 2019 to report that Campbell was threatening to kill Jasmine and Jaida. She also reportedly claimed that Campbell said she would end her own life.

Campbell “was at times hysterical” and would not share her location as she claimed the twins were already dead, now-former Suffolk County Police Commissioner Geraldine Hart said in 2019.

Police reportedly found Campbell’s parked minivan at around 4 p.m. at the entrance of Montauk County Park in Montauk. AsCBS Newsreported in 2019, police used cell-phone tracking to locate the vehicle. Hart said at the time that Campbell screamed for officers to shoot her.

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Citing a police statement based on the testimony of the victims' grandmother, CBS News also reported that Campbell claimed she killed the children “with my bare hands” and that she was “driving to a beach” to “find the ocean and walk into it so she could be with her babies in heaven.”

The outlet also shared that the grandmother claimed Campbell had a “very long history” of mental disorder, depression, bipolar and anxiety and that she was “acting very irrational and angry.”

Campbell’s then-4-year-old son was in his father’s custody at the time of her arrest.

Campbell, who pleaded guilty before Suffolk County Supreme Court Justice Richard Ambro on Wednesday, has a sentencing conference on Jan. 25.

If you suspect child abuse, call the Childhelp National Child Abuse Hotline at 1-800-4-A-Child or 1-800-422-4453, or go to www.childhelp.org. All calls are toll-free and confidential. The hotline is available 24/7 in more than 170 languages.

source: people.com