The bodies of Shatikey Griffin and her daughter were found inside the home after the standoff ended. Griffin's father, Thaddeus Griffin, said he was the one to identify the victims.
While Smith was holding police at bay in southwest Atlanta, officers in East Point found the body of Lovett Wallace, 36, inside a hotel room at the Wellesley Inn. They say the crimes appear to be connected.
Hundreds of classmates, teachers, family and friends gathered at KIPP WAYS Academy, where Demiya was an honor roll student.
"She always had a smile on her face, very positive girl," said one girl.
"I just miss her and her memory is incredibly powerful, and when I think about her and the things that she's done and conversations we've had -- I just get excited when I think about her," said another girl.
Family members said incredible outpouring of love and support meant a lot as they try to understand an unimaginable crime.
"I felt like I was the only one left. I felt like he took everything away from me, but to see all these people and know it's a lot of people behind me, to know that I have a lot of support -- it just helps," said Dearilus Floyd, Tiki Griffin's son and Demiya's brother.
The Griffin family says Tiki had planned to marry Smith next month and they had no hint of a dark side.
"He was a fun-loving, cool guy, so that's why we don't understand what happened, like what brought him to that point," said Duwon Robinson, the victim's cousin. "I don't think he was sober-minded, because like I said, that's just not his character."
"Our family is so sad behind this tragedy. We loved our sister, we love our family and this has been very hard," said Shelbe Griffin-Deadwyler, the victim's sister.
FOX 5 News has learned the Griffin family, including Tiki and Demiya, participated in the Atlanta Heart Walk on Saturday.
"Tiki and Demiya were just a mother and daughter who had a great bond as fun loving," said Robinson.
FOX 5 News has learned that Smith has been arrested several times, dating back to 1999. In 2009, he was arrested for abandonment of a minor child. In 2003, he was arrested for battery, and for sexual and simple battery in 1999.
Smith has a 14-year-old daughter, police have confirmed.
Smith is expected to face a judge on Tuesday. Police say the postponement was due to medical reasons. He is being held in the Fulton County Jail.