SUTTER COUNTY -- All Emma Cunningham has to hold onto are memories and photographs after her sister was taken from her last year.
"There's really nothing except pictures left of her," Cunningham said. "I want to be able to call her and that’s the worst part is I can’t even call her anymore."
Katherine was murdered -- decapitated -- in February of 2018. Her mangled body was found in Camano Island, Washington.
"My first thought was him. It automatically went to him as soon as I heard what had happened. And that was my first question is, 'Where’s Jacob?' and nobody knew where he was," Cunningham told FOX40.
Katherine moved to Camano Island in 2015 with her boyfriend, Jacob Gonzales. It felt sudden to her family.
"She just showed up one night and said they were moving to Washington and she left," Cunningham said.
Katherine and Gonzales were both Air Force reservists. They dated on and off for several years.
"I was not a big fan of him, but it was her choice," Cunningham told FOX40. "He would never come around us and so I thought that was kind of weird. You know, if you’re dating someone you go around their family and he just wasn’t a very social person."
Neighbors found Katherine’s body on March 3 in a wooded area. She was wrapped in a sleeping bag and left in a red wagon near a bunker stocked with guns and ammunition.
Her car was nowhere in sight and neither was her boyfriend.
Gonzales became the prime suspect in the case. He was the subject of a multi-state manhunt but investigators say he had a two-week head start.
"The California Highway Patrol contacted us and let us know that Katherine’s car, which was missing from our scene, had been left abandoned on I-5 near Yreka around February 16," said Island County Sheriff's Detective Ed Wallace.
Wallace says they found a samurai sword in the trunk.
"There was blood on the sword that matched Katherine with her DNA and the suspect, Jacob Gonzales', DNA was found on the handle of the sword," he explained.
For several months, detectives followed up on leads, while Cunningham made a Facebook page called "Justice for Katherine" to keep her sister's story alive.
"You have to do everything you can do to get justice for them," she said. "That was my main goal on the page."
And it worked.
In November, 10 months after her sister's murder, Cunningham was contacted on Facebook by someone following her page, showing her a news story with pictures of a man found floating in the Feather River in Sutter County. Authorities had not identified the body but released photographs of his tattoos.
"As soon as I saw the tattoos, I knew, that's him," she said.
She called the Sutter County Sheriff’s Office, who sent John Doe’s DNA to the Department of Justice for testing.
Months later, investigators had a match.
"We were notified that it was a positive match. Our John Doe was, in fact, the suspect from the state of Washington," Sutter County Sheriff Brandon Barnes said.
It was Jacob Gonzales. He had drowned.
It's unknown if Gonzales took his own life or if his death was an accident.
The discovery brought mixed emotions for Katherine's family.
"A part of me didn't want it to be him," Cunningham said. "I did want him to answer for what he had done."
When Gonzales died so did the hope of getting any answers for why he killed Katherine.
"That's going to be the hardest thing is to never know what happened that night or that day," Cunningham told FOX40.
Investigators say Gonzales was their only suspect, but the case is still open. They plan to continue to collect evidence as if the case was going to trial, all to make sure no stone is left unturned.
Meanwhile, Katherine's sister is finding comfort in the memories, praying she is watching over her family.
"I mean, I hope she would be proud of me. I tried to do whatever I could for her," Cunningham said. "That was my main goal was just getting answers for her, justice for her."