Sheena May was the only witness Sunday in the courthouse in Magnolia, telling jurors her divorce had become final in recent days, the Daily Leader newspaper reported.
The woman's ex-husband, Willie Cory Godbolt, 37, is charged with capital murder, accused of fatally shooting the eight, including the deputy who arrived at his in-laws'home that Memorial Day holiday weekend. Prosecutors are seeking the death penalty.
May testified that she and Godbolt had been together 17 years, married seven of those, with two children. She said they had separated many times over the years and and she was living with her mother when the shootings occurred.
The killings began after Godbolt entered the in-laws' home in Bogue Chitto and got into an argument with his estranged wife and her family over the couple's two children, witness Vincent Mitchell testified earlier, according to The Daily Leader.
Mitchell said Godbolt fatally shot then responding deputy and then killed Godbolt's mother-in-law and two other people. Godbolt then went to two other homes in south Mississippi's Lincoln County, killing two of his teenage cousins and a husband and wife, investigators have said.
In Sunday's testimony, May said she had been at her mother's house for two months, adding, "I chose my life over my marriage. He was very abusive to me, controlling."
She said she had called 911 when her sister told her Godbolt had arrived and was outside the home. "I called the police because I was afraid of him," she testified, adding she sent her two children to stay in a bedroom.
She told jurors she had gone into the living room and Godbolt was then coming in through the kitchen, telling her mother "it was time for them to listen."
May said the arriving Lincoln County sheriff's deputy, William Durr, entered the home and asked Godbolt to leave when those present saw Godbolt pull a gun from behind his back and shoot Durr in the face.
May testified that she ran to the bedroom, knocked out a window out and ran with her children to a neighbor's home, calling 911.
Godbolt's attorney Katherine Poor told the jurors earlier in the trial that her client was trying to protect his family and didn't want his daughter staying at the home, since he believed she had been inappropriately touched by a family member there.
"Cory just snapped," Poor said. "Cory couldn't see the breakup of his family. He couldn't fail to protect his children. In that moment in a haze of fear at the breakup of his family, Cory pulled his gun out."
Godbolt has pleaded not guilty to four counts of capital murder, four counts of murder, one count of attempted murder, two counts of kidnapping and one count of armed robbery. He has remained in custody since his arrest on May 28, 2017, hours after the shootings.
Because of pretrial publicity in south Mississippi, jury selection was conducted in north Mississippi's DeSoto County, 285 miles (459 kilometers) north of Lincoln County. The 12 jurors and three alternates were selected Friday. They are hearing the case in Magnolia, which is near Lincoln County.
The trial was scheduled to continue Monday.