Butler police are investigating a fatal stabbing early Sunday at an apartment on the 100 block of West Jefferson Street, authorities said.

The victim, 43-year-old Robert Wagner, who lives at the apartment above the China Palace restaurant, was pronounced dead about 2:40 a.m. at the Butler Memorial Hospital emergency room.

An autopsy was conducted about 10:30 a.m. and determined Wagner died of a stab wound to the chest, said Butler County Deputy Coroner Larry Barr. The manner of death is pending.

Butler police are releasing few details about their investigation, and they would not say if there are any suspects. No one was in custody as of 2 p.m. Sunday.

Police and emergency crews were called at 2:07 a.m. for the reported stabbing at the apartment. Wagner's girlfriend called 911, authorities said.

Butler Fire Department and Butler Ambulance Service medics treated the victim, who was still breathing when he was taken by ambulance to the hospital.

Police released no other information and declined further comment when contacted.