Watch: 'It was murder' - US man's chilling confession to brutal cold case stabbing 25 years on

The brutal and callous 1993 murder of a US teenager has this week been solved after the perpetrator handed himself in, citing the "nightmare" guilt he has lived with for 25 years.

Californian man Brian Keith Hawkins, 44, handed himself in to the Shasta County Sheriff’s office for the stabbing of 19-year-old Frankie Wesley McAlister in Northern California's Shingletown in 1993.

The murder had remained unsolved ever since, but Hawkins revealed he and two accomplices, siblings Shanna Culver, 46, and Curtis Culver, 45 were responsible for the stabbing.

But before Hawkins handed himself in he spoke to local TV station KRCR, revealing the torture he had lived under for the past 25 years.

"Horrible, horrible, horrible, absolute horror, absolutely horrible since that day," Hawkins told the station.

"Every minute of every day has been a nightmare.

"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.

"I know the wrong can’t be changed but this is the closest I can come to doing the right thing."

Hawkins was arrested following his confession at the Shasta County Sheriff’s office, and his accomplices apprehended the following day.

KRCR reporter Courtney Krieder said Hawkins simply walked into the station and said he wanted to confess to McAlister's murder.

"He refused to answer any questions about the case itself but said he wanted people to know that he had found God, and that is what led him to finally do the right thing and confess," Krieder said.

"He was visibly emotional and asked for a soda and a 'smoke' before going on camera."

Redding Police, now investigating the case, say the believe the motive McAlister's murder was the robbery of money he had recently got from a settlement.

Investigators said the trio met McAlister under the guise of selling him methamphetamine in Shingletown, but proceeded to rob and stab him to death.

CNN reported McAlister's 81-year-old grandmother said the arrests brought her some relief.