The UK national handed himself in to Gardaí just days after the savage 2019 killing at Hyde Road in Limerick, which left the city and the boxing world stunned.
Until his trial began in the Central Criminal Court, Jackson had been in a protection cell in Limerick Prison and was not allowed to mix with other inmates for his own safety.
Sunday World sources, authorities have information that there is a real threat to Jackson's life following the murder of the popular 20-year-old boxer as he walked home from a house party.
He is expected to be returned to Limerick Prison after he was sentenced yesterday to life for the killing.
Jackson had been kept on a prison landing which also hosts Dublin gangster 'Fat' Freddie Thompson, who is serving life for the murder of Daithi Douglas.
Fat Freddie is currently fighting a legal battle to reverse the decision by prison bosses to transfer him to Limerick Prison.
It is likely that at some point in the future Jackson will be repatriated to the UK to serve out his life sentence, sources added.
Jackson had to have a foot amputated after being shot in the UK while in hiding from a gang which had made threats to his family.
Details of the shooting emerged during a court hearing in 2017 when Jackson was convicted of possessing two 9mm bullets.
He pleaded guilty to the offence on the basis that the bullets, which had been converted from blanks, had been put through his letterbox as a threat from a notorious Coventry-based gang.
The 31-year-old had turned up in court in a wheelchair and, according to his defence lawyer, had been effectively in hiding and living a nomadic existence.
It was added that the threats stemmed from claims that a family member owed a debt to the 'P1 Crew' and that Jackson had subsequently been shot in the foot.
No details were given as to the circumstances of the shooting, except that the injury resulted in him losing his foot.
The P1 Crew saw several members jailed in 2013 for a multi-million pound conspiracy to import cocaine from Holland and have a reputation for violence and intimidation.
The bullets had been discovered by police along with a machete when they raided Jackson's home.
An assault charge against Jackson at the time was dropped when the complainant twice failed to turn up in court.
Kevin Sheehy's murder left Limerick and the boxing community deeply shocked.
At yesterday's sentence hearing his mother Tracey Tully told of the devastating impact his death has had on their family.
"I'm still stuck on July 1 2019 and I haven't a single enthusiastic bone in my body."
She said she will never forget the morning when she was woken up to be told that her son was badly injured. "I panicked when I saw his dad's face, it was grey.
She also spoke of how proud she was of her son: "Even though Kevin has passed on, I love being his mother. I'm so proud of my boy."
During the trial there was harrowing testimony about how Kevin Sheehy tried to get up after being mown down by the Mitsubishi Shogun driven by Jackson.
His cousin, Thomas Lysaght, told how he tried to grab on to Mr Sheehy before he was struck by the speeding vehicle, and then tried to help as the car spun around for a second run.
"I had to let Kevin go and move away. He was dragged up the road," Mr Lysaght told the trial.
In a moving statement read to the court yesterday Mr Lysaght also spoke of the incredible pain his murder has caused.
"The pain of losing Kevin is unbearable. I have had very dark days and nights. I have many times not wanted to be in this world. The only thing that keeps me here is knowing Kevin saved me that night and I will not let him down."
"I will do my best to be there for his mother, sister and baby girl."
There was little heard during the trial as to why Jackson flew into such a murderous rage and turned his vehicle into a deadly weapon in the sudden attack.
Jackson had claimed he had felt intimidated and threatened by "three big fellas" who threatened him outside a house party.
However, the men with Kevin Sheehy said there was nothing to the brief exchange and no-one had acted in a threatening manner.
CCTV of the encounter showed there nothing physical during the encounter.
Jackson's claims of being threatened and his car surrounded by a crowd were found to be untrue by the jury.