Investigators believe a domestic dispute led to the shooting at Zion Hope Missionary Baptist Church about 11 a.m., said Second Deputy Police Chief James Tate.
A 9-year-old child, sitting near the unidentified woman who died, was hit in the hand by a buckshot pellet, Tate said. Police didn't know the relationship of the pair.
As the gunman fled the church, he critically shot a man trying to protect his wife from a carjacking attempt, officials said. Many of the hundreds of people in the church screamed as they ducked under the pews for protection, said Ann Armstrong, 30, who was attending the service.
"I seen him come in through the balcony door, and he pulled the gun from under his coat," Armstrong said. "He just started shooting her, then he shot at the pulpit."
No one at the pulpit was hit, but a bullet struck a musical instrument she said.
More than five hours after the shooting spree, Tate said officers spotted the suspect, who was identified as 24-year-old Kevin Lorenzo Collins, walking about a mile south of the church. Collins shot himself to death before police captured him, Tate said.
Church members embraced each other after the gunman left and continued to pray as police started coming in, Armstrong said.
"It was a lot of crying, a lot of hugging and a lot of praying," she said.
Church members then continued the service, Tate said. "They didn't let this incident stop the reason why they came to church," he said. "They came to worship."