On Jan. 9, a victims’ advocate and a law-enforcement official showed up on Metzler’s doorstep. They gave her the news her entire family had feared for more than 22 years: The body in California was, in fact, her sister. Diana had been murdered.

A homicide investigation is under way, according to Cindy Bachman, a spokeswoman with the San Bernardino Sheriff’s Department — a department that has a team devoted to working on cold cases.

But even then, “cold cases often take the backseat to cases that are fresh and we have some leads on,” she said. “We have to focus on the recent cases first.”

When it comes to missing-adult cases, Bachman she said that in her position she finds that it can be difficult to draw any media attention to cases that don’t involve children or senior citizens or some public figure. She said reports on TV or in newspapers can be critical in solving missing-adult cases early on.

“It is sometimes difficult to get media attention if there’s nothing sensational that goes along with the story to maybe make it interesting for viewers or readers,” she said. “That can make it difficult to get any public assistance.”

She acknowledged law enforcement’s struggle to determine if people are truly missing or have simply walked away from their lives.

“It’s just a really tough situation,” she said. “There are tons of missing people. Some of them don’t want to be found.”

Today Metzler thinks her sister wanted to leave home back in 1991, but she doesn’t think Diana was looking to disappear.

Even more, Metzler said she fears that her sister’s killer won’t be brought to justice — that the person who murdered Diana when she was just 19 might be out there somewhere. That the killer might know who Metzler is too.

Even after so much time, Metzler still gets upset when she talks about her older sister.

“I think, once they confirmed it, that’s the hard part. Because you know you’re not going to see her again. There were people saying she was married, had a kid — none of that is true,” she said through tears. “I haven’t really dealt with it because I’ve just learned all this stuff, you know? It’s not easy.

“I mean, I shouldn’t say I’m glad that (my parents) passed away. But I know my mom would not have been able to handle hearing that her daughter was murdered.”