CHICAGO (AP) — A Chicago man has been sentenced to 90 years in prison for brutally killing his ex-wife on Thanksgiving Day 2011.

Cook County State’s Attorney Anita Alvarez said Tuesday that 52-year-old Earl Roberts was convicted of first-degree murder in the fatal shooting of 48-year-old Angela Bonds. Court records show Roberts ambushed Bonds and her fiancé as the victim left work at UIC Hospital.

Prosecutors say Roberts followed Bonds after she clocked out at 11:50 p.m. and walked to her car with her fiancé. Roberts used a revolver to shoot Bonds in the back. After Bonds fell, Roberts fired a bullet into the top of her head.

Roberts fled on foot and left a trail of physical evidence. Police recovered the gun, Roberts’ clothing and the gloves he wore.