JACKSONVILLE, Fla. -

Detectives with the Jacksonville Sheriff's Office have arrested a 58-year-old man in connection with a shooting death at The Retreat at St. Johns apartment complex off Kernan Boulevard on Monday.

Robert Francis Schulze (pictured) has been charged with murder in the death of 57-year-old Charlotte Whitehead Branton.

Branton, who had been dating Schulze, was found shot to death inside her apartment at the complex at 4790 Seascape Way in Jacksonville. Schulze was the one who called 911. Police originally told News4Jax they did not suspect foul play in Branton's death.

According to the arrest report, Schulze originally told homicide detectives he was at the apartment to help Branton move, found her unresponsive and attempted to perform CPR after dialing 911.

At the scene, officers discovered a spent shell casing but did not locate a weapon, the report said. Investigators with the Medical Examiner's Office confirmed to detectives that the wound near Branton's head was not consistent with suicide, and following an autopsy, her death was ruled a homicide, according to the report.

Further investigation revealed Schulze and Branton were breaking up and Branton was moving out of state and breaking off their engagement, the report said. Branton's cellphone records showed text messages between herself and Schulze that implied Branton was afraid of Schulze and did not want to see him, according to the report.

Detectives also found that Schulze had driven to Branton's apartment two times on the day she died, the report said.

Schulze was arrested Thursday and booked into the pre-trial detention facility on a charge of murder.