A tibia bone found in Humboldt County has been traced back to a San Francisco man who vanished in 2017, according to authorities.
A woman, Kim Cabrera, discovered the bone sticking out of the banks of the Eel River back in July, and on Monday the Humboldt County Sheriff's Office confirmed it belonged to Mark Burleigh, 39.
Burleigh, who's been missing since October 2017, was last seen in Garberville - a town in Humboldt County - where he was staying with friends, according to a missing person poster that has circulated since his disappearance first unfolded.
The sheriff's office said he last made contact with a friend after he was released from the Humboldt County Correctional Facility earlier that month.
Following her chilling discovery, Cabrera, a Student Information Technician, said she 'immediately' knew it belonged to a human, but never thought she would know them.
Cabrera was left speechless after she was informed it it belonged to Burleigh, who she knew from her time working as a teacher's aid at Myers Flat Community School in the late 1990s.
'Once they had confirmed that it was human by checking with the coroner, then they sent a deputy out to come to get the bone, and they took it with them to do DNA testing on it at that point, and I had no idea that was going to turn out to be somebody that I knew and that was quite a surprise and a shock at the time,' Cabrera told KRCR TV.
She vividly remembered Burleigh as a kid who was 'just full of life.'
A left tibia bone found in July by a woman, Kim Cabrera, is confirmed to belong to Mark Burleigh, 39, (pictured) who vanished back in October 2017
Cabrera, who knew Burleigh when she was a teaching aid at his school in the late 1990s, located the bone sticking out of the banks of the Eel River
'He was an entertaining kid, he was really energetic, just full of life, he seemed like he had a good future ahead of him and he was super young, he still had his whole life ahead of him at that time and he was just a good kid to work with,' Cabrera told the outlet.
Although his tibia bone was found over the summer, search efforts, including K9s, could not locate additional remains.
His mother, Jennifer Burleigh, does not understand why more of her son's remains weren't found, as she has waited years for answers.
'Last night, I just kept on wondering, there’s got to be more of him. I gave birth to a whole body…Please don’t give up, I need my son,' she told authorities and the community, according to local outlet Redheaded Blackbelt.
Although his tibia bone was found over the summer, search efforts, including K9s, could not locate additional remains. (Pictured: Eel River)
His mother, Jennifer Burleigh, does not understand why more of her son's remains weren't found, as she has waited years for answers. (Pictured: The tibia bone)
She has continued to post about her son's mysterious disappearance in hopes of figuring out what happened to him.
The Humboldt County Sheriff's Office is still investigating Burleigh's case and has urged the public to contact them with any related information.
Meanwhile, Cabrera is still trying to wrap her head around the fact that she found his bone.
'It brought all these memories back of what he'd been like as a kid, and what a special kid he was and so it was a moment of grief and sadness, and I am still processing it, it is still very sad to me that it turned out to be him,' she said.