Police said Saturday that 33-year-old Jessie L. Dotson was arrested Friday night and is the older brother of Cecil Dotson, one of the victims.
Police Director Larry Godwin announced Saturday that Dotson had been charged with six counts of first degree murder and three counts of attempted first degree murder after a four-day investigation into the homicides.
The bodies - four adults and two children - were discovered Monday at a small rental house where three other children also were found critically wounded.
Cecil Dotson, 30, was the father of the dead and injured children.
Authorities identified the other adult victims Wednesday as Hollis Seals, 33; Shindri Roberson, 20, and Marissa Rene Williams, 26.
Cemario Dotson, age 4 and Cecil Dotson, age 2, were the two boys found dead in the home.
Roberson's family told CBS News affiliate WREG they can't believe Dotson's brother is behind bars for the gruesome crime.
"Destroy your own brother and his kids and whoever else is around that is not a brother. That man is possessed by a devil," said Verle Jones, Roberson's aunt.
Jones added, "That's not a brother. He's just a cold blooded, cold hearted person."
Records show that Jessie Dotson pleaded guilty to second-degree murder in 1994 and spent 14 years in prison. He was released from prison in January.
Police say the four adults died from apparent gunshot wounds and the children suffered multiple injuries as result of stab wounds.
Neighbors who live the street where the murders occurred are also shocked. Many thought the crime had to be the work of a number of people, not just one person.
"It's just shocking to everybody. We're just trying to figure out what's going on in our neighborhood. We really don't know," Thomas Miles told WREG.
The surviving children are under police custody at a children's hospital and authorities refuse to give the extent of their injuries.
Susan Steppe of Le Bonheur Children's Medical Center won't talk specifically about this case but says in cases like Lester Street, "there is a watchful eye on those children every minute."
Steppe told WREG, "I realize to the public outside the hospital it may seem that these children are being deprived of important relationships that would be very important to them right now. But I want to assure you that every child at Le Bonheur is being tended to."