Brian Joseph Carey, 41, was arrested in Trumbauersville Borough by state troopers on charges of possession of a controlled substance and possession of drug paraphernalia.
He is being held at the Bucks County Correctional Facility under $750,000 bail.
Officials say the homicide investigation is active and ongoing.
Carey was being sought as a person of interest in the killing of his stepfather, 78-year-old Joseph Michael Jakimowicz.
Officers in Bristol Township were dispatched to the 700 block of Winder Drive at about 7:15 p.m. Tuesday. When police arrived, they found Jakimowicz dead inside the home.
Police are also asking anyone with information on the investigation to contact Bucks County Detectives at 215-348-6354 or Bristol Township Detectives at 215-785-4040.