A son and grandson of a 95-year-old Washington County woman, strangled by another grandson in what defense attorneys called a mercy killing, are now charged with conspiracy in connection with her death.

Gordon Twiss, 73, and David Twiss, 52, are both charged with second-degree conspiracy in the July 2017 death of Leonna Twiss. Gordon is Leonna's son, and David is his son and her grandson.

Kevin Gonyea, another grandson, pleaded guilty to strangling her with a towel.

Leona Twiss was suffering from Alzheimer's and dementia, and Gonyea had moved back from Florida to take care of her.

Gonyea's wife Melissa also pleaded guilty to helping him dispose of the towel used to kill Twiss.