By CBS3 Staff

MORRISVILLE, Pa. (CBS) – A mother and her adult daughter have both been sentenced to five consecutive life sentences for killing five of their relatives. Shana Decree and her daughter, Dominique, pleaded guilty but mentally ill in a Bucks County courtroom and were sentenced on Monday morning.

(credit: CBS3)

Authorities say they killed five of their relatives, including three children at their Morrisville apartment back in 2019. 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.

Four of the victims were suffocated, one was strangled.

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

The Bucks County chief deputy district attorney explained that a finding of guilty but mentally ill versus the insanity plea is complicated.

“In this case, what they knew was they were killing people. And what they knew was they shouldn’t be killing people. Even if you’re doing it for reasons that are inexplicable, or maybe reasons that are rooted in mental illness, when those two factors are in play that’s guilty but mentally ill and not insanity,” Christopher Rees said.

A Bucks County Children and Youth Social Services caseworker discovered the bodies during a wellness check.