After being released from a 20-year prison sentence having served just 3, he also killed his own uncle and 4-year-old niece, and stabbed his aunt in both eyes, investigators say.
An Oklahoma man cut his neighbor's heart out and cooked it for his family, before killing them too, police say.
Lawrence Paul Anderson, 42, is accused of murdering Andrea Lynn Blankenship, 41, as well as his own uncle Leon Pye, 67, and his four-year-old niece Kaeos Yates.
On February 9, Chickasha police responded to a 911 call from a home on West Minnesota Avenue, in which a woman pleaded for help. Arriving on the scene they heard a woman yelling, and forced their way in.
Inside they found Leon already dead, his granddaughter Kaeos critically injured. She died in the back of the ambulance on the scene. Delsie Pye, was still alive, but with knife wounds to both eyes.
"Chickasha Police Officers observed Anderson throwing up in the living room into some pillows," Oklahoma State Bureau of Investigation said.
But it wasn't until two days later, as Anderson was being treated for injuries in hospital, was the full extent of the horrific crime revealed: he confessed that before slaughtering his family, he had first broke into one of his relatives' neighbor's houses and butchered the woman who lived there too, OSBI claimed.
"He confessed to going to 227 West Minnesota Avenue, Chickasha," an agent wrote in a request for a search warrant of the Pye house. "He used his shoulder to knock in the back door. There were two German Shepherd dogs in the house. Anderson advised he killed the female resident and cut her heart out."
"He took the heart back to 214 West Minnesota, Chickasha," the agent told the judge. "He cooked the heart with potatoes to feed to his family to release the demons."
Among the evidence the agent wanted to collect from the home were "pots, pans and any utensils for cooking."
The appalling case has sparked further outrage as it emerged Anderson is a convicted felon and repeat offender, who should have been serving 20 years in prison, had his sentence not been dramatically reduced.
Per The Oklahoman, he was first sent to prison in 2006 for four years for attacking his girlfriend, pointing a gun at her and possessing crack cocaine with the intent to distribute; however he was released after just two.
In 2012 he was sentenced to 15 years for selling crack cocaine near an elementary school in Chickasha; he was released after just five years.
Less then five months after his release in 2017, he was sentenced to 20 years for breaking probation, when he confronted a woman at her car in a church parking lot; he was carrying a gun and had a vial of PCP hidden in his underwear.
However, Governor Kevin Stitt commuted the sentence to nine years at the recommendation of the Oklahoma Pardon and Parole Board. He was released after serving just three.
After his release on January 18, he was taken in by his aunt and uncle — the same aunt and uncle he would be accused of stabbing three weeks later.
"This has to be addressed by the Legislature, sooner rather than later, because more people are going to get killed," Grady County District Attorney Jason Hicks said.
He plans to charge Anderson on Tuesday, and said that the death penalty "is on the table."