Mosley was identified as Eley's assailant by Raymond L. Tucker, who said he heard screams coming from the victim's home on the 800 block of South Vogdes Street and then saw the beating through an open door.
Tucker said he pulled Mosley off Eley, who lived independently despite having suffered a stroke five years earlier, and threw the suspect outside.
"He said I needed to mind my own business," Tucker testified. "I told him, 'This guy is an old gentleman. You don't get no stripes for that.' "
Tucker said Mosley fled and he called 911 and waited for the ambulance. A motive for the beating was not established during Wednesday's preliminary hearing.
Assistant District Attorney Jan McDermott said Eley was taken to the Hospital of the University of Pennsylvania but never regained consciousness.
Eventually Eley was discharged to a rehabilitation center, but was rehospitalized several times for pneumonia and other infections before going into hospice care in December, McDermott said.
Defense attorney Gerald A. Stein asked Hayden to dismiss the homicide charges, arguing there was no way to prove Eley died of injuries from the April 1, 2012, beating.
Stein said that Eley's relatives signed a "do not resuscitate" directive when he entered hospice and that no efforts were made to save him when he developed a fatal infection.
McDermott, however, cited the testimony of Eley's cousin and caretaker, Valerie Spivey.
Spivey said Eley had walked to his doctor and the barbershop; she said she did his own shopping and laundry.
McDermott said Eley's injuries and subsequent infections were an "unbroken chain. . . . His life steadily deteriorated. He couldn't walk, he couldn't talk, he couldn't take care of himself."
Philadelphia Assistant Medical Examiner Marlon Osbourne testified that the autopsy in January still showed evidence of brain bleeding and bruises from the attack.
Eley's case was one of a series of attacks this year on elderly Philadelphians.
The day before Mosley was arrested, police charged a 42-year-old North Philadelphia man in a Feb. 25 home break-in and attack that killed a 95-year-old woman.
Tito DeJesus was held for trial at a July 23 preliminary hearing in the death of Alice Sanders.
Contact Joseph A. Slobodzian at 215-854-2985, firstname.lastname@example.org, or @joeslobo on Twitter.