State Police are looking Michael Marchalk of Barnesville, Schuylkill County.
The son - who was supposed to enter a rehab program on Monday - fled the location and his father's corpse was found the next day.
Marchalk was charged in a warrant with homicide, aggravated assault, robbery and related offenses following his father's death.
State police said in a complaint filed Wednesday that 37-year-old Michael Marchalk had repeatedly threatened 60-year-old Gary Marchalk in recent months.More news: Hospital: Scalise upgraded to fair condition
According to the criminal complaint, another family member, Matthew Marchalk, called police when he found his father's body on June 19.
Michael Marchalk was hit with multiple charges, including murder and theft of a motor vehicle.
He was last seen at a Philadelphia bus terminal, but authorities say he may still be driving his father's gold Ford Fusion with the license plate JWD1566.
"It is very tragic that a son could do that, or to me, that anyone could do that, let alone your own blood", Trooper David Beohm said.
He was a well known attorney in the Schuylkill County area.