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MORRISVILLE, Pa. (CBS) — A mother and daughter are claiming they killed five family members because everyone in the household wanted to die, police say. Sources say 45-year-old Shana Decree, and her daughter, 19-year-old Dominique Decree, strangled the victims over the past couple of days in their Morrisville apartment. Shana and Dominique Decree have been charged with five counts of criminal homicide and one count of conspiracy to commit criminal homicide.

From left to right: Shana S. Decree, 45, and daughter Dominique Decree, 19.

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The victims include Shana Decree’s children — 25-year-old Naa’Irah Smith, and 13-year-old Damon Decree Jr. — as well as Shana Decree’s sister, 42-year-old Jamilla Campbell, and Campbell’s 9-year-old twin daughters, Imani and Erika Allen.

Photo of Jamilla Campbell. (credit: CBS3)

A Bucks County Children and Youth Social Services case worker was doing an unannounced wellness check Monday afternoon inside the first-floor apartment at the Robert Morris Apartments on West Bridge Street, and discovered a bedroom full of dead and semi-conscious family members, in what police believe as a murder-suicide attempt.

From left to right: Damon Decree, Imani Allen and Erika Allen. (credit: CBS3)

Shana Decree and Dominique Decree were rushed to the hospital after being found in the apartment. One was found unconscious and the other was seizing.

Credit: CBS3

According to an affidavit released on Tuesday, Shana Decree told police everyone in the apartment, including the 9-year-olds and 13-year-old, wanted to die. Decree allegedly said they had all been talking about suicide.

“We will do our best to get justice for those two girls and those three other victims,” an emotional Bucks County District Attorney Matt Weintraub said during a press conference Tuesday afternoon.

Weintraub said all eight family members lived inside the apartment.

“Frankly, we’re still trying to sort everything out,” the DA said.

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At the hospital, the suspects allegedly told police it was everyone’s wish to commit suicide. Police are not buying it.

“When you have two 9-year-olds involved, two 9-year-olds can’t make that decision, and a 13-year-old. Is it something in the adults’ minds? I don’t know, but it’s surely not in 9-year-old minds,” said Morrisville Police Chief George McClay. “It’s a sad day for us. As much as I’ve seen over my career, this is the saddest case I’ve ever had.”

Shana Decree is being held without bail at the Bucks County Jail. Her preliminary hearing is scheduled for March 5 at 9:30 a.m. Dominique Decree was arraigned by video and was also denied bail. Weintraub says she is still receiving medical treatment and being watched by police.

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Police say 17-year-old Joshua Campbell, the son of Jamilla Campbell, has been found safe after authorities were searching for him. He is not a suspect in the case.

The scene is still being processed, but authorities say it may take weeks to unravel how and why these five people were killed.

“It will be some time before we can determine the causes of deaths,” said Weintraub.