A Virginia mother who fed her children sleeping pills before shooting them in their beds to punish her ex-husband was sentenced Friday to 78 years in prison.

Veronica Youngblood, 38, was arrested in August 2018 for the murders of 15-year-old Sharon Castro and 5-year-old Brooklynn Youngblood in their McLean apartment. 

"I’ve been a good mother, but something happened, I don’t know how to explain it," she told the judge in Fairfax County District Court through a Spanish interpreter before her sentence was handed down. "Something exploded in my mind."

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Woman looks downcast next to photo of little girl holding a teddy bear.

Veronica Youngblood's booking photo from Aug. 6, 2018, after she shot her daughters to death. (Fairfax County Police Department via AP/ Facebook)

Sharon did not die immediately and managed to call 911 to tell a dispatcher that she had been shot by her mother. Jurors were so traumatized after hearing a recording of the harrowing call, they asked if they could receive therapy.

Ron Youngblood said that his ex-wife slipped the children the melatonin-laced gummies and shot them to death Aug. 5 to punish him.

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"Those girls were leverage to her — leverage to get what she wanted from me," the 52-year-old Navy veteran told The New York Post. "She obviously knew those girls were the most important things in my life."

The couple was supposed to move to Missouri together, but Veronica changed her mind at the last minute. Ron fought to take Brooklynn, his biological daughter, and Sharon, Veronica's daughter from a prior relationship.

Ron Youngblood poses with an American flag and his daughter next to a photo of him in his Navy uniform.

Ron Youngblood with his biological daughter Brooklynn Youngblood, and his ex-wife's daughter from a prior relationship, Sharon Castro. Both girls were murdered by their mother, Veronica Youngblood. (Facebook)

After a judge ruled that he could take Brooklynn, Veronica began plotting the depraved crime and bought a gun one week before the murders, prosecutors said.

She shot Brooklyn in the head and Sharon in the back and chest, then called her ex-husband to tell him that she hated him and murdered the children.

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"She saw that she had no more tools to use against me, so she decided to get rid of them," he told the newspaper.

Veronica pleaded not guilty by reason of insanity, but jurors rejected the defense and recommended the lengthy term the judge imposed.

Veronica Youngblood smiles in a selfie with her daughter.

Veronica Youngblood murdered her daughters Brooklynn Youngblood and Sharon Castro Aug. 5, 2018. (Fairfax )

The jurors heard testimony during the trial that Veronica was physically and sexually abused as a child and turned to sex work as a teenager to support her eldest daughter. She grew up in poverty in Argentina.

The defense asked Fairfax County Circuit Court Judge Randy Bellows to let her serve the two murder sentences concurrently instead of consecutively, which would have reduced her time behind bars to 42 years – but he declined.

"Mothers and fathers have many responsibilities, but none is more grave than keeping their children safe," he said. "Tragically, their mother became the instrument of their death."

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Ron, who was in court for the sentencing, said that he knew his ex-wife felt anger toward him. "[But] never once did I imagine that she could do anything like that to our girls," he said.

The Associated Press contributed to this report.