The mother and daughter charged with killing five of their relatives in suburban Philadelphia admitted to police that they planned a murder-suicide because everyone “wanted to die,” according to reports.

The disturbing scene unfolded inside a two-bedroom apartment in Morrisville, Pennsylvania about 50 kilometres northeast of Philadelphia — where child welfare officials found victims Naa’Irah Smith, 25, Damon Decree Jr, 13, Jamilla Campbell, 45, and nine-year-old twins Imani and Erika Allen slain in one of the bedrooms.

Shana allegedly told investigators that “everyone of the apartment including the nine-year-olds and 13-year-olds wanted to die and that everyone was talking about suicide,” reported, citing a probable cause affidavit.

At first, the mother and daughter — who were rushed to a local hospital — denied knowing what happened, the affidavit said.

In the hospital, Shana, 45, initially claimed that Campbell’s boyfriend and two unknown men killed everyone — except for her and Dominique. But she later walked back that claim and confessed to killing one of the children. She said she and Dominique also killed a second child.

The pair also blamed one of the deaths on Campbell — with Shana accusing her slain sister of killing Smith.

Dominique, 19, then killed Campbell, Shana told police.

Dominique allegedly admitted to strangling Campbell and said she and her mother murdered two of the children and Smith. Dominique also claimed that Campbell choked one of the kids to death, though it’s not clear which one.

“This is a terrible tragedy. I just spoke with the family of the five deceased, and we’re all heartbroken,” Bucks County District Attorney Matthew Weintraub said at a press conference. “I wish I had better news to report.”

“I wanted to come out here,” he added, “and make sure that everybody knew that the people that committed these atrocious acts are now in custody and will be made to pay for their crimes.”

Mr Weintraub said that authorities were concerned for the welfare of Campbell’s 17-year-old son Joshua but had later made contact with him. He stressed that the teenager was not a suspect in the slayings and that they had just wanted to “ensure his safety.”

The bodies were found around 4pm (8am AEDT) on Monday by the case worker who was conducting a wellness check at the home and had asked a maintenance worker to check the apartment when no one answered.

When the maintenance worker gained access to the apartment, he reportedly found Shana and Dominique Decree in bed. He told police that they seemed disoriented and the apartment was in disarray. Police were called to the scene and both were taken to the hospital.

According to the affidavit, arriving officers saw furniture up-ended in the apartment, along with broken glass and clutter. Welfare officials told police the apartment was not in disarray during their last visit in early February.

Police initially reported that they saw four bodies in one bedroom, but the fifth was later discovered underneath another body.

The two women were taken to a hospital. There was no information immediately available about their condition.

Police said Dominique Decree had sustained neck injuries and initially denied knowing what happened. According to 6ABC in the US, she reportedly claimed that an unknown male hurt her and kept saying that she wanted to die.

Shana Decree also reportedly denied knowing what happened, telling police that her sister’s boyfriend and two other men came into the apartment and killed everyone except her and her daughter.

She also reportedly told police that everyone in the apartment, including the nine-year-old twins and 13-year-old, wanted to die and were talking about suicide.

According to the affidavit, Dominique told police how each person was killed. She said her mother and Campbell killed the others and then she killed Campbell through choking.

Police have not disclosed a motive, and the case is still under investigation.

The causes of death remain under investigation. Morrisville Borough Police and Bucks County Detectives are investigating.

Shana was held without bail following her arraignment Tuesday morning local time. Dominique is awaiting arraignment.