Police in Pennsylvania arrested a mother and daughter for killing five family members, including three children, inside their Bucks County home in a murder-suicide plot.

According to police, Shana Decree, 45, was arraigned on five counts of murder and one count of conspiracy charges and her 19-year-old daughter, Dominique, is expected to be arraigned on the same charges, reported WPVI-TV.

Both Shana and Dominique confessed to killing their relatives.

The five family members killed have been identified as Shana’s children, Naa'Irah Smith, 25, and Damon Decree Jr., 13, both of Morrisville, Shana's sister, Jamilla Campbell, 42, and Campbell's 9-year-old twin daughters, Imani and Erika Allen.

Campbell’s 17-year-old son was found safe at a friend’s house, reported NBC Philadelphia.

In a Tuesday afternoon press conference, Bucks County District Attorney Matthew Weintraub said it will take weeks before the exact causes of death are determined.

"To be able to resolve a case in which five people were murdered within the course of a half a day and have the two people responsible locked up and facing justice is amazing and a true testament to the quality of law enforcement that we enjoy here in Bucks County. It doesn't make it any easier, but I'm at least grateful to say that everybody out there is safe and not at risk from these killers," Weintraub said.

The bodies were found after Bucks County Children and Youth Social Services Agency performed a welfare check at the apartment on Saturday. When no one answered, the representatives came back Monday and asked a maintenance worker to open the apartment.

Upon entering the home, the worker found Shana and Dominique Decree in bed while the rest of the apartment was in disarray with scattered furniture and broken glass.

The police were then called to the scene, where they found the bodies in a bedroom.

Although the mother and daughter denied the killings at first, Shana later told police everyone in the apartment, including the 9-year-old twins and 13-year-old, wanted to die.

According to the affidavit, Dominique then told police how each person was killed. Dominique said Shana killed one twin, the 13-year-old, and Smith and that Campbell killed the other twin and then strangled Campbell.