ATLANTA — The Georgia Supreme Court has reversed the malice murder and cruelty to children convictions of a Forsyth County man found guilty of beating to death his girlfriend’s 2-year-old son in 2009.

Christopher Brian Gilreath, then 41, was found guilty by a Forsyth County Superior Court jury of murder, two counts of felony murder, aggravated battery, two counts of first-degree cruelty to children and possession of cocaine in the death of Joshua Pinckney.

In the unanimous opinion released Monday, Justice Carol Hunstein wrote that the trial court made a “reversible error” by refusing to allow Gilreath’s attorney to use testimony from the girlfriend’s ex-husband about her alleged abuse of her two children.

According to court documents, Miriam Pinckney was at the Catalina Drive home the day of her young adopted son’s death.

She was also indicted for felony murder and first-degree cruelty to children, based on her failure to get her son the medical care he needed.

She pleaded guilty in August 2010 to cruelty to children and was sentenced to 20 years, with the first five to serve in prison and the remainder on probation.

Though she could reveal the next steps, Forsyth County Chief Assistant District Attorney Sandra Partridge said retrying Gilreath for murder is an option.

Partridge, who handled the trial in 2010, said she and those on behalf of the state did not expect the reversal.

“We’re very disappointed,” Partridge said. “We respect, of course, the opinions of the court, but we disagree.”

According to court documents, Pinckney and her then-husband, John Pinckney, adopted two babies from Guatemala — Joshua, born in September 2006, and Maria, born in February 2007.

When the couple’s marriage began to unravel in 2008, according to the opinion summary, Pinckney rekindled a high school romance with Gilreath, eventually relocating to Cumming.

During this time, Pinckney’s ex-husband maintained visitation rights.

He insisted on setting up a webcam to see the children after Gilreath’s dog bit Maria Pinckney on the cheek and required stitches in January 2009.

According to the summary, John Pinckney did not see injuries on either child on Feb. 10 or 11, 2009, via webcam.

On Feb. 12, 2009, Miriam Pinckney left her children at home with Gilreath while she went to work.

“According to prosecutors, Gilreath was resentful both of his unemployment status and being asked to babysit Joshua and Maria,” the summary said.

She left work in the middle of the day to help change a “really bad diaper” and was told by Gilreath the young boy was taking a nap in the bedroom.

She then checked on the boy, but did not pull down the covers from his shoulders.

On her way home from work later that day, Gilreath called and said Joshua “must have fallen because he had a bruise on his check and a scrape on his face.”

She applied ointment to the scrape when she got home before going grocery shopping. She did not check on him that night when Gilreath said he had changed Joshua’s diaper and put the covers back on him.

The next morning, she found her son “laying in a puddle of vomit, and it was obvious to her he was dead. Pinckney began screaming then dialed 911.

Although Gilreath reported to medical personnel that Joshua had been breathing that morning, first responders later testified that the child showed no signs of life, had been dead for some time and was bruised on his face and abdomen.”

An autopsy showed the 2-year-old suffered six blows to his head and sustained injuries to his face, forehead, mouth, stomach, bottom, groin, legs and the inside of his mouth.

A medical examiner said the toddler most likely suffered the injuries and died eight to 10 hours before 911 was called.

During the trial, prosecutors asked to not allow Gilreath to use testimony from John Pinckney that Miriam Pinckney had a history of threatening “both children with violence and had once slapped Maria in the face.”

The testimony was not allowed, and the jury subsequently convicted Gilreath on all charges. He was sentenced to life in prison.

This Supreme Court reversal of all charges except the possession of cocaine stemmed from Gilreath’s appeal that the evidence was insufficient to convict him and that he was prevented from presenting a complete defense.

The high court found that the evidence was sufficient to find him guilty but that “the trial court was wrong to deny him the opportunity of questioning John Pinckney about Miriam’s treatment of the children.”

John Pinckney would have testified he saw his ex-wife slap her young daughter “in the face for refusing to eat breakfast and that he considered reporting the incident to child protective services; that she would cuss at the babies or threaten them with beatings when they were too young to understand; and that she had indicated she wanted to send the children back to Guatemala.”

However, the opinion said, “because we determined that the evidence was sufficient to support the original convictions, double jeopardy does not bar the state from retrying Gilreath on counts one through six.”