Forty-four-year-old Brian Keith Hawkins turned himself into California police on Tuesday over an unsolved cold case murder-from 1993.
The 44-year-old Hawkins refused to give any details about the killing in Tuesday's interview but said living with the secret had been "absolutely frightful".
'Every minute of every day has been a nightmare, ' he said.
"It's kind of weird, Frank never got to have a life, but we were teenagers and now I'm 44 and still haven't even had a life and now most likely won't anyway", he continued.
After speaking with reporters, Hawkins went to the Redding Police Department, where cops say he admitted to having a role in McAlister's death.
A hiker found McAllister's remains a year later, police said.
According to police, Hawkins told them he and his siblings lured McAlister to the Shingletown area in an attempt to rob him.
Investigators said that Hawkins' confession was their first big break in the case.
"God, Christ - these things that have happened throughout my whole life since then, for over 25 years, have pushed me and pushed me to do the right thing", Hawkins said. The money was from a settlement he received following a vehicle crash he was in two months before he was killed.
Acting on that statement, police also arrested Curtis Culver, 45, and his sister, Shanna Culver, 41, after finding them Wednesday in the nearby community of Red Bluff, authorities said.
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Police have since arrested Hawkins, along with his alleged accomplices, 46-year-old Shanna Culver and her brother, 45-year-old Curtis Culver. McAlister had a large amount of cash that the trio wanted to steal to buy methamphetamine, Hawkins said.
McAlister was reported missing by his family shortly after he disappeared. "The trio then took his money and vehicle and drove back to Redding, abandoning the victim's vehicle".
'I know the wrong can't be changed but this is the closest I can come to doing the right thing'.
All three suspects were taken to jail by the Shasta County Sheriff's Office.
Hawkins and Curtis Culver stabbed McCalister to death and left his body in the woods, the release said.
The station told law enforcement officials that they would not report the story until its journalists could corroborate what Hawkins told them.
He was arrested on Tuesday following his confession, and the Culver siblings were arrested the next day.
He said he reached out to McAlister's family previous year to ask for forgiveness and vowed to confess to the crime. He also said some God stuff before finishing his Pepsi and cigar, then heading out to turn himself in.
Anyone with information can contact investigators at the Redding Police Department at 530-225-4200.