On the morning of May 17, 2005, 48-year-old Patricia Ann Trish McDermott was found dead on a Market Street sidewalk in Philadelphia after stepping off a SEPTA bus en route to her job as an X-ray technician at Pennsylvania Hospital. She had been shot once in the back of the head; there were no signs of robbery or a struggle and her belongings were left with her.

Surveillance footage from a nearby post office captured a man disembarking the same bus, following McDermott and raising an arm to shoot her before fleeing. A bus company employee later identified the man as regular rider Juan Covington, who also worked at the hospital as a subcontractor hauling medical waste. Hospital camera footage showed him entering the building in the same clothes shortly after the killing.

Covington was arrested July 12, 2005, and confessed, saying he believed McDermott was poisoning him with X-rays. He also admitted to other attacks and killings. To avoid a death sentence he pleaded guilty and was sentenced in March 2006 to three consecutive life terms. Did anyone who knew Trish or worked at Pennsylvania Hospital notice anything unusual about her routine before May 17, 2005?