The day after he replaced his Facebook picture with that of a shotgun shell, a Chester County man shot and killed his longtime girlfriend, officials said.

Gregory Twyman, 44, was charged with murder in the Tuesday slaying of Jamica Woods in East Fallowfield Township.

According to the affidavit of probable cause, Twyman called 911 and said, "I need the police. I just shot my girlfriend."

On Monday, the affidavit said, Twyman altered his Facebook profile picture to that of a shotgun shell. When a friend warned that he might get in trouble, Twyman replied on his page, "Once I handle my business, I don't give a . . .."

Police said they found the victim on the master bedroom floor with gunshot wounds to an arm and midsection. Police recovered a single-shot 12-gauge shotgun at the scene.

Twyman was arrested at his house by Police Chief Chris Porter, Chester County District Attorney Thomas Hogan said. The case is being investigated by local police and Chester County detectives.

Contact Aubrey Whelan at 610-313-8112, awhelan@philly.com, or follow @aubreyjwhelan on Twitter.