The body of Alice Hufnagle, 67, was found in an upstairs bedroom of her suburban Philadelphia home, and a blood-stained Scream mask was among clues found at the killer's home. 

Rhonda Smith, 42, was found face down and shot twice in a church office in Springfield Township when a close friend stumbled upon the horrifying scene.

Alberto Martino, 54, was found lying in a pool of blood outside the radio station where he was a disc jockey after wrapping his show. He had "serious wounds around the head."

Authorities discovered a "horrendous scene" after rushing to the Bensalem, Pennsylvania apartment of Christian Rojas, whose friend found him dead in a bathtub.

After the lifeless body of Elaine Goldberg, 21, was found in a vacant lot in the Kensington neighborhood of Philadelphia, two other women were found dead in similar, brutal fashions. 

Dr. James Sowa, a 64-year-old chiropractor, was found bleeding and unconscious in his home. Investigators traced the crime to a suspect who was angry at him for a shocking reason. 

Surveillance video showed someone firing a gun at the back of Patricia McDermott's head. When Juan Covington emerged as a suspect, police were shocked by what came next.   

Since being released from prison for a 2008 manslaughter, Keith Gibson has been convicted of killing two in Delaware and is suspected of killing four others in Philadelphia. 

After Chester Police Department Corporal Michael “Mike” Beverly was murdered in Pennsylvania,  investigators used a "radical maneuver" to track down his killer. 

Chris McMullin, host of a new Oxygen True Crime show about murder cases in Philadelphia, was inspired to go into law enforcement after a sweet encounter with police as a child.