EL CAJON, CA -- A fitness instructor, who once managed three Bally Total Fitness locations in Virginia and Chicago, was recently convicted of second-degree murder.

Geraldine Meyers, 46, faces 40 years to life in prison at a sentencing hearing set for March 4 in El Cajon (CA) Superior Court, according to the San Diego Union-Tribune. Meyers doused her ex-boyfriend with pepper spray before and after shooting him twice in the back of the head. Demetrious James Warren, 30, a former bodybuilder, was killed on Nov. 20, 2006 while he played video games in the bedroom of his apartment, the newspaper reported.

Meyers’ conviction took place Feb. 1 after a trial in which she testified that she used the pepper spray on Warren because she was trying to protect herself from a possible attack. Meyers also testified that she had been in an abusive relationship with Warren, with whom she shared the apartment before she moved out in October 2006.

Deputy District Attorney Kurt Mechals contended in court that the shooting was murder because Meyers testified that she had bought the gun months earlier and had it tucked in her waistband when she confronted Warren in the bedroom, the newspaper reported. Just before the shooting, Meyers and Warren had argued over who should pay the rent on the apartment, Warren’s romance with another woman and Meyers’ fear that Warren had infected her with a sexually transmitted disease, according to the Union-Tribune.

Prior to her managing the Bally clubs, Meyers was a part-time aerobics instructor. She later taught kickboxing, worked as a personal trainer and studied to become a massage therapist. Leading up to the shooting, Meyers taught exercise classes at the Marine Corps Recruit Depot in San Diego. She was separated from her then-husband, a former Marine drill instructor, when she met Warren in December 1998 in Virginia, the newspaper reported.