Murdaugh’s attorneys Dick Harpootlian and Jim Griffin said in a statement that new evidence had come to light since his March conviction over the brutal 7 June 2021 slayings.
This evidence will form the basis of a new motion requesting a retrial in the high-profile case.
The attorneys – who are longtime friends of the killer and represented him at his high-profile murder trial – will reveal this new evidence and release the motion at a press conference on Tuesday afternoon.
The briefing is scheduled to take place on the grounds of the South Carolina State House near the Court of Appeals in Columbia at 2.30pm local time.
For now, the details remain a mystery.
Murdaugh is currently behind bars at the McCormick Correctional Institution in South Carolina where he is serving two life sentences for his wife and son’s murders.
Last week, it emerged that Murdaugh had lost some of his prison privileges after he fed information to a Fox Nation documentary without permission.
South Carolina Corrections Department officials said on Wednesday that, during a jailhouse phone call on 10 June, Mr Griffin had recorded him reading aloud entries from the journal he had kept during his double murder trial.
Mr Griffin had then handed over the recordings to producers working on the new Fox Nation documentary about his high-profile case titled “The Fall of the House of Murdaugh”, released today.
Prison policy prohibits inmates from talking to the media without permission because the agency “believes that victims of crime should not have to see or hear the person who victimized them or their family member on the news,” state prisons spokesperson Chrysti Shain said in a statement.
The media interview violation, along with another violation for using a different inmate’s password to make a telephone call, are prison discipline issues and not a crime, Ms Shain said.
As a result, the disgraced legal scion has had his phone privileges revoked and his prison tablet computer confiscated.
Murdaugh also lost his ability to buy items in the prison canteen for a month.
He will now have to get permission from prison officials to get another tablet, which can be used to make monitored phone calls, watch approved entertainment, read books or take video classes, the prison spokesperson said.
Mr Griffin was also issued a warning from prison officials that if he knowingly or unknowingly helps Murdaugh violate rules again, he could lose his ability to talk to his client.
Phone calls between lawyers and prisoners are not recorded or reviewed because their conversations are considered confidential.
But prison officials said they began investigating Murdaugh after a warden reviewing other phone calls heard Murdaugh’s voice on a call made in a different inmate’s account.
Murdaugh claimed that his phone password had not been working. He also told the prison investigators about the recorded journal entries, according to prison records.
Murdaugh’s use of a jailhouse tablet previously hit headlines when selfie images he took on the device were obtained in a Freedom of Information request by FITS News.
In many of the images, the convicted family killer appeared topless.
South Carolina prison officials later clarified that the photos are automatically taken as an inmate uses their tablet that is individually assigned to them – as part of inmate monitoring.
Now, Murdaugh has lost the use of his tablet indefinitely due to his unauthorised communication with the documentarymakers – which marks his first media interview of sorts since his conviction.
His eldest – and now only surviving – son Buster Murdaugh also broke his silence speaking out in his first TV interview as part of the three-part series.
In the interview, Buster insisted that he still believes his father is innocent of the murders of his mother and brother – but admitted that he may be a psychopath.
Maggie and Paul were found shot dead on the family’s 1,700-acre Moselle estate back on 7 June 2021. Alex Murdaugh had called 911 claiming to have found their bodies.
During his high-profile murder trial, jurors heard how Paul was shot twice with a 12-gauge shotgun while he stood in the feed room of the dog kennels on the affluent family’s 1,700-acre Moselle estate. The second shot to his head blew his brain almost entirely out of his skull.
After killing Paul, prosecutors said Murdaugh then grabbed a .300 Blackout semiautomatic rifle and opened fire on Maggie as she tried to flee from her husband.
During the dramatic six-week trial, Murdaugh confessed to lying about his alibi on the night of the murders but continued to claim his innocence of the killings.
The jury didn’t agree and the disgraced legal scion was convicted in March of the brutal murders.
Beyond the murder charges, Murdaugh, 55, is also facing a slew of financial fraud charges for stealing millions of dollars from his law firm clients and his dead housekeeper’s family.
He is expected to plead guilty on 21 September to federal charges – marking the first time he has pleaded guilty to a crime in court.
Murdaugh is also facing around 100 financial charges in state court as well as charges over a botched hitman plot where he claims he paid an accomplice to shoot him dead.
Murdaugh’s high-profile conviction also shone a spotlight on some other mystery deaths tied to the South Carolina legal dynasty.
Following Maggie and Paul’s murders, investigations were reopened into the 2018 death of the Murdaugh’s longtime housekeeper Gloria Satterfield and the 2015 homicide of gay teenager Stephen Smith.
Meanwhile, at the time of his murder, Paul was also awaiting trial for the 2019 boat crash death of Mallory Beach.