Shana Decree and her daughter, Dominique Decree, have been charged with the slaughter of five family members, including 9-year-old twins.
Police said they discovered the bodies in a Bucks County apartment around 5:30 p.m. She said that she killed one of the victims, that she and her daughter Dominque killed another together, and that Campbell killed two other victims before she herself was slain by Dominique.
Shana told police "everyone at the apartment... wanted to die" and talked about suicide, according to court documents. No ages or names were released by police, who are still on scene investigating. "I just spoke to the family of all five of the deceased and we're all heartbroken".
Shana and Dominique Decree then told police about a complicated plan that allegedly involved some of the victims killing each other - at least one being choked to death - and then Shana and Dominique Decree killing the rest, according to the court records.
Dominique has been charged with five counts of homicide and one count of conspiracy. Her daughter is expected to be arraigned today.
The bodies were found Monday in an apartment in suburban Philadelphia after Bucks County child welfare officials showed up unannounced and got no response when they knocked on the door.
The victims included Shana's children Naa'Irah Smith, 25, and Damon Decree Jr, 13, as well as Shana Decree's sister Jamilla Campbell and Ms Campbell's nine-year-old twin daughters Imani and Erika Allen.
District Attorney Matthew Weintraub said the mother and daughter were residents of the apartment in which the five relatives were found.
They said the apartment was "in disarray, with furniture turned over and with broken glass and clutter throughout". They also found Shana and Dominique Decree in bed acting "disoriented".
The accused killers told police that the two mothers took turns killing their children before the older Decree strangled her sister. Dominique claimed an unknown black male had caused injuries to her neck, and that she "repeatedly advised her wish to die", the probable cause affidavit obtained by CNN says.
Shana was held without bail following her arraignment Tuesday morning.
According to police, the search continues for Campbell's 17-year-old son, Joshua Campbell, who authorities believe managed to escape the violence.
"She was a happy person, happy person and cared for people", Hall said.