Dominique Haynes, 33, was taken into custody by the Philadelphia Police Homicide Unit and the U.S. Marshals.
He was being sought in connection with the death of his girlfriend, 27-year-old Rasheedah Blunt, who was shot on Tuesday night while her 6-year-old daughter and a 3-year-old cousin slept in the next room.
Blunt was shot at least five times in the chest, torso and arms, inside the apartment on the 3500 block of Old York Road in the Hunting Park section of the city around 11:30 p.m.
Police found her body on a bed on the second floor front bedroom.
The killing went down in the apartment the two had shared since September.
Neighbors told police they heard a loud domestic argument rage in her second floor apartment, then multiple gunshots and then saw a man fleeing the scene.
Haynes, who has a lengthy criminal record, immediately became the number one suspect.
Police say Haynes has been out of jail for less than a year.
Police say the children did not wake up until officers arrived.
The family has told Action News, Christmas present donations for the 6-year-old can be sent to:
6644 Lansdowne Avenue
Philadelphia, Pa. 19151