A Warren man accused of killing his grandmother with a hammer has entered a plea of “guilty, but mentally ill.”

Juston K. Moore, 19, was charged with criminal homicide in the June 10 death of Kelly D. Wadsworth, 60, also of 619 Fourth Ave. She was Moore’s grandmother.

Moore was in Warren County plea court before President Judge Maureen Skerda on Thursday, where he entered the plea to first-degree murder charge as well as abuse of a corpse. He entered a guilty plea to theft by deception at a separate docket.

A hearing regarding the “mentally ill” portion of the plea and sentencing will be scheduled and probably held on the same day, according to Skerda.

Moore was represented by Warren County Chief Public Defender Kord Kinney.

District Attorney Rob Greene said the sentence for first-degree murder is mandatory life in prison without parole. Greene said he had talked with the family and “there is no just outcome of this case.”

Moore said he understands that he will spend the rest of his life “in the prison system.”