'Happy Face Killer' Keith Jesperson claims he's been 'cured' in prison in new letter written from behind bars where he's serving time for strangling eight women then sending notes to media with smiley faces on them

The 'Happy Face Killer' has claimed he has been 'cured' by his time behind bars, and says he'll never commit another crime again.

Keith Jesperson, 67, from British Columbia, Canada, killed at least eight women while traveling America's highways as a long-haul rig driver in the 1990s. 

He earned his notoriety by sending gloating confessions to police and journalists and signing them with a smiley face.

The twisted killer said in a letter addressed to NewsNation reporter Ashleigh Banfield that he was desperate for his freedom. 

'Freedom feels so special to me,' Jesperson wrote.

'Most (inmates) are angry and want some kind of payback... Time behind bars has cured me, I am no longer that person that put me in here.' 

The letter was one of several he has sent to NewsNation journalists. Laura Ingle received five double-sided letters written by his hand as a prisoner of Oregon State Penitentiary, where he is serving a life sentence without parole. 

Keith Jesperson, 67, (pictured) from British Columbia, Canada, killed at least eight women while traveling America's highways as a long-haul rig driver in the 1990s 

Jesperson killed at least eight women, including Julie Ann Winningham and Suzanne Kjellenberg

He claimed to have killed up to 160 people during his prolific career as a serial killer 

The letters come just weeks after a California woman recently discovered that the her sister was the last unidentified victim of the Happy Face Killer that was discovered through DNA testing.

Summer Gonzales, who lives in Seattle, said that she never knew she even had a half-sister until she was contacted by law enforcement in California about a year ago.

Gonzales's family member, whose name has not been identified, was killed sometime in the 1990's and her body was dumped on the side of a highway in Blythe County, California.

In 1992, the woman's killer, Keith Hunter Jesperson, aka The Happy Face Serial Killer, confessed to the murder, along with seven other murders he committed during a cross-country killing spree.

He called his female victim 'Claudia,' though investigators believe that Claudia may not be her real name, Riverside County Sheriff Investigator Amy Contreras told CBS8 News said.

Gonzales expressed frustration that officials have not released her sister's remains to the family and said that she wants 'to get justice and to find the truth for my sister.'

The victim, who was a frequent hitchhiker, is believed to have met Jesperson, who worked as a long haul truck driver, at a truck stop.

Contreras told the news outlet that 'it is suspected in the morning before her death, she caught a ride with Jesperson, who was traveling from Las Vegas or the Barstow region along the I-15 near the Cajon Pass.

Authorities in Florida were able to identify Suzanne Kjellenberg (pictured) as one of Jesperson's victims, using forensic technology and DNA evidence

According to the investigator, 'Claudia' then walked over to Jesperson while he was working on his purple 1989 Peterbilt. The pair traveled down the I-10 east to the Burns Brothers truck stop near India.

The pair stopped at a diner and then had a heated argument while in Jespersens truck and that is where he killed her.

Additional reports cited that Jesperson had raped the young woman than strangled her before dumping her body on the side of the road in Blythe County, California.

Jesperson, who claimed to have killed up to 160 people during the late 1990s' was charged with killing eight woman across the country.

He was nicknamed the Happy Face Serial Killer for placing a 'smiley face' on many confession letters he had written, as per the news outlet.

The Riverside County District Attorney, Michael Hestrin said 'this woman is the last of all his victims to remain unidentified.'

Gonzales said her father, Alfonso Saldana Gonzales, Sr. fathered at least nine children with five women.

Convicted murderer Keith Jesperson, right, shown here at a November 2, 1995, court appearance in Portland, Oregon

Jesperson has sent several letters about his crimes

She said that she wasn't shocked that her father had so many children, but said she was 'devastated' to learn the news that one of his daughters was a victim of the Happy Face Serial Killer.

Her father died in 2006, but said that she remembered his character as being somewhat of a 'ladies man.'

'He had a lot of women when he was younger, even in his old age, he had plenty of girlfriends hanging around everywhere,' she said.

Earlier this year, she sent photos of her dad to the news outlet hoping it might reveal the identify of her her half-sisters mother.

'If anybody recognizes the pictures of my father, and they knew his whereabouts between the years of 1964 and 1967, he would have lived either in Harris County, Houston, Texas, or Santa Barbara County, which is Santa Maria, California,' Gonzales said.

She said that none of her known family members was able to identify her new -found relative.

Gonzales said she has been in despair since Riverside officials won't release her sister's remains to the family so they can have a funeral.

'It would be nice to know her real name. It would be wonderful if I could find her mother's name so that I could include those items on her tombstone,' she said.

'But I know that she is my blood. And I want to lay her to rest with her family. I'm sure that she would have wanted that, too,' she said.

Contreras told DailyMail.com that they have been in communication with the victim's half-sister, Summer Gonzales.

She said that 'due to the victim not being identified, the coroner's office is unable to release the remains until positive identification has been made.'

But added, 'once positive identification is made, the coroner's office will be able to determine who the actual next of kin is and make arrangements with the family for a proper burial.'

According to officials, the woman was between ages 25 and 35 at the time of her death.

She was described to be about 5 feet 7 inches tall with medium build, with brown hair possibly dyed blonde. She also had a tattoo of two black dots on the side of her right thumb.

Investigators said the unidentified murder victim's mother may have been from southeast Texas or Louisiana.

Gonzales added, 'we are of Mexican descent, so it's more likely that the person that was my sister's mom, she would have lived among Mexican people.'

The Riverside County Sheriff Officer Investigator said any information may help and explained that 'no call would be insignificant to us.'

'[He] dumped her on the side of the road like she was trash and she's not,' Contreras told ABC13 Las Vegas News.

'She deserves dignity and respect. Just try to think back. Anything you can remember that can trigger a memory, call us.'