Joyce Garrard, an Alabama woman who was sentenced to life in prison for the 2012 murder of her 9-year-old granddaughter, died Friday, less than a year into her sentence.

The cause of her death remains unclear, but Garrard was suffering from health complications at the time. She collapsed Sunday at the Julia Tutwiler Prison for Women in Wetumpka sometime after a visitation with her family, reported NBC's Alabama WVTM-TV. Prison guards found her unresponsive, and she suffered a heart attack soon after. She was given emergency care after being found to be brain dead and then airlifted to Jackson Hospital, where she remained on life support until she died Friday.

"This is another loss for a family that already has lost so much," defense attorney Dani Bone said.

Garrard was sentenced to life in prison without parole in March 2015 after she was convicted for capital murder in the death of her 9-year-old granddaughter Savannah Hardin after she made her run as punishment for lying about eating candy, reported Alabama.com. She was rushed to the hospital after losing consciousness and died after never regaining it. Evidence at the trial revealed that Hardin had been forced to run for more than three hours without rest.

Garrard argued that she never intended to harm Hardin and was running alongside her while they talked about the importance of telling the truth.

"If she was running, I was running," Garrard said, noting that she was also trying to teach her granddaughter how to run faster in school races.

However, prosecutors gave a different account of the incident, calling Garrard the "drill sergeant from hell" and described the child's death as agony imposed by a woman she loved and trusted - an account that jurors ultimately believed.

"She was tortured," prosecutor Carol Griffith told jurors in closing arguments, according to the Associated Press.

Tragedy has befallen the family for a third time with this death, and a fourth may be just around the corner, as Jessica Mae Hardin, child's stepmother, is set for trial in June on a murder charge for allegedly failing to stop the punishment. She has pleaded not guilty to the charge.