Christine Lyons, 47, was found guilty by a Supreme Court jury on Thursday of murdering Samantha Kelly, and of attempted murder over a failed attempt on her life days earlier.
But the killer’s former lover Ronald Lyons, who is not related to Christine, was cleared of murdering 39-year-old Ms Kelly.
Instead, he was convicted on the lesser charges of attempted murder and assisting an offender.
Ms Kelly, a disability pensioner, was struck repeatedly to the head with a hammer by Lyons’ current partner Peter Arthur in a bungalow behind their house in January 2016.
The Lyons were both found guilty of attempting to murder Ms Kelly with a cocktail of prescription and over-the-counter drugs before her eventual death at Arthur’s hands.