Senior Superintendent Isagani Nerez, city police chief, identified the suspected gunman as Benedict Fassong, a native of Sadanga, Mountain Province.
Lawyer Eugenia Vinluan Campol was shot four times with a caliber .45 pistol as she was about to enter her house in Woodsgate Subdivision in Barangay Camp 7, killing her on the spot.
A second suspect, Benjamin Amrangeb, who reportedly served as a lookout, was also charged.
A massive manhunt is ongoing for the two suspects, whom witnesses have positively identified as the ones behind the killing.
Nerez said Fassong has pending warrants of arrest for murder and frustrated murder.
The police said Campols killing might have something to do with politics and personal grudge between her family and an influential official in Abra.
Campol was a former public attorney in her husbands hometown of Boliney in Abra.