Alicia Fox's two young children, were still missing and the investigation is focused on finding them, Police Chief James Craig said.
Erin Justice, 28, was detained Wednesday as a fugitive from justice. Homicide detectives from Detroit were on their way to Atlanta to interview him, Craig said, and he could face a murder charge.
Relatives last saw Fox, 27, her son, Kristian Justice, 8 months, and daughter, Kaylah Hunter, 6, on May 24. The family searched the city for days until an uncle found her body on Monday in the basement of an empty house.
The Wayne County Medical Examiner's Office said Fox was shot twice in the head and had other bullet wounds. A law enforcement source told the Detroit Free Press that a police search of the house she shared with Justice and the children found a bullet lodged in a wall with signs that someone had tried to conceal the damage.
A 27-year-old Detroit man has also been arrested in the case and is likely to be charged as an accessory, police said.