A Pennsylvania mom was arrested Tuesday for allegedly smothering her son to death and attempting to kill her daughter as well — all while texting their father to say she was doing it, police said.

Police announced Wednesday that 21-year-old Christian Clark was charged with homicide and attempted murder in the aftermath of the tragedy.

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Police said that Clark and the children’s fatherm Andre Price Jr., were having an argument about his alleged infidelity when she started texting things like, "Ya kids ain’t safe here I don’t want them here... So you better pray for your kids” and, “I’m killing them,” with a laughing emoji.

Police said she then sent a video of the child’s lifeless body, letting the dad know that she had killed the 17-month-old.

Police said the parents were exchanging texts before, after, and during the act.

Superintendent of the Allegheny County Police Department, Coleman McDonough, said Clark confessed to killing the baby during an interview with police.

“She admitted to smothering her son in an air mattress,” McDonough said. “At one point she lifted the child’s lifeless body [on video]... and texted that video to the child’s father.

Police said additional texts also revealed that she unsuccessfully attempted to smother her 2-year-old daughter.

“It’s quite an exchange,” McDonough said of the text messages. "Obviously she was angry and he was denying her allegations. It just goes to show how have texts have become such a part of our lives that people don’t even realize the nature of what they are communicating."

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Clark called McKeesport police after the incident and told them she found what she called the boy unresponsive, police said.

Both children were taken to the hospital where the 17-month-old was pronounced dead.

The 2-year-old is expected to be okay.

Clark is currently being held without bond until a preliminary hearing.

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