Dorchester man pleads guilty to killing his mother in 2020

A Dorchester man pleaded guilty Monday to second-degree murder in the strangulation death of his mother in their home in 2020.

A Suffolk Superior Court judge sentenced 25-year-old Zackery Grandy to life in prison, with the possibility of parole at 20 years, according to the Suffolk County District Attorney’s Office.

On Feb. 26, 2020, Grandy attacked his mother, 51-year-old Gisel Thomas, while she was on the phone with a clinician from the Boston Emergency Services Team seeking mental health assistance for him, a statement from the district attorney’s office noted.

“The clinician heard what he believed was Grandy attacking the victim and called 911,” the statement noted.

Boston police went to the home on Columbia Road in Dorchester, but no one answered the door, according to the DA’s office.

The next afternoon, the victim’s brother discovered her body, prosecutors said.