In that case, the father, whose name was not released, is expected to be charged with murder, Homicide Sgt. Bob Wilkins said.
He was allegedly watching his children, an 11-month-old boy and his 2-year-old girl, by himself Saturday morning at their home on Edgley Street near 22nd, in Strawberry Mansion, when, he said, he found the baby unconscious on the bedroom floor at about 6:45 a.m.
Medics rushed the boy to Temple University Hospital, where he was pronounced dead at 7:01 a.m.
Investigators are awaiting autopsy results from the Medical Examiner's Office, but Wilkins said that the baby boy was bruised over his head and body.
The 2-year-old girl was not injured, he said.
In the other suspected case of child abuse, a 3-month-old girl who was taken to Temple by her 16-year-old mother and 20-year-old father at about 11 p.m. Saturday was found to have "really severe injuries," said Officer Tayna Little, police spokeswoman.
The child was transported to St. Christopher's Children Hospital from Temple when she began having multiple seizures, police said.
There, doctors discovered that she had been suffering from multiple contusions and bleeding in the liver, Little said.
The parents, who live with their daughter on Emerald Street near Cumberland, in Kensington, are being investigated by police, though no charges had been filed as of last night.
The infant remains in critical condition at St. Christopher's, police said.
Also on Saturday, Craig Artis, 45, was charged with the Friday morning death of his elderly mother at the home they shared on 46th Street near Woodland Avenue, in West Philadelphia, police said.
Artis broke the neck of his 83-year-old mother, Bessie Artis, with his bare hands, police said.
He was on scene when police responded to the house at about 8:47 a.m. for reports of screaming and found Bessie Artis on the kitchen floor. Medics pronounced her dead within minutes, Wilkins said.