(CNN) -- Not knowing. It's the hardest part.
That's the truth facing the loved ones of slain or missing Americans.
So when a 19-year-old Pennsylvania woman already facing murder charges told a newspaper reporter that she'd killed before -- over and over again, from Alaska to North Carolina -- loved ones couldn't help but sit up and take notice, said Kristy Dyroff, a spokeswoman for the National Organization for Victim Assistance.
"Anyone hands them the least glimmer of hope, they latch on to it," she said. "The biggest difficulty for victims is they have no control, and they're trying to regain some by doing something proactive."
On Sunday, the Daily Item newspaper in Sunbury, Pennsylvania, published a jailhouse interview with murder suspect Miranda Barbour in which she claimed a string of killings dating back six years -- to when she was 13.
"I would lure these people in," the Daily Item quoted her as saying. "I studied them. I learned them and even became their friend. I did this to people who did bad things and didn't deserve to be here anymore."
Barbour took credit for more than 22 but fewer than 100 killings, Daily Item reporter Francis Scarcella told CNN affiliate WNEP. Authorities haven't verified her claims, although they are investigating.
Barbour and her husband, Elytte Barbour, 22, do face murder charges in the 2013 death of 42-year-old Troy LaFerrara, who police say was strangled and repeatedly stabbed by the couple before being dumped in a yard.
If her other claims are true, Barbour would be one of the nation's most prolific serial killers.
Gary Ridgway, known as the Green River Killer, pleaded guilty to killing 49 women in Washington state in the 1980s and 1990s. Randy Steven Kraft may have killed as many as 65 young men in the 1970s and early 1980s.
Based on the numbers she gave Scarcella, Barbour would have had to kill on average somewhere between every three weeks and every three months. For six years. Without leaving a trace.
Yet in the 2013 killing, police documents show Barbour told police she and her husband couldn't clean up all the blood LaFerrara's killing left in her CR-V, and that one of the ways investigators traced the killing to her was her own cell phone. The last number dialed on LaFerrara's phone led to Barbour, according to police.
Even the prosecutor who hopes to convict the couple, Northumberland County District Attorney Tony Rosini, said he discounts Barbour's other claims.
"We have been in contact with other law enforcement agencies where she has lived and haven't received any information verifying what she said," Rosini told WNEP.
That means little to loved ones of victims clinging to a desperate need for answers -- and there are plenty of people in that situation.
The FBI estimates more than 87,000 people were missing in the United States at the end of 2012. And in just the last five years, more than 26,000 killings have gone unsolved.
In North Carolina, where Barbour and her husband lived before moving to Pennsylvania, advocates for families of missing persons and crime victims have already heard from some people asking about possible links to the case.
"Anytime anything like this happens, we start getting e-mails and phone calls. I started getting texts last night," said Monica Caison, the founder of the Wilmington-based Community United Effort Center for Missing Persons.
"It sends everybody into a panic mode -- a hopeful panic mode," Caison said. "They want to be one of those, but they don't want to be one of those. They want their nightmare to end."
Some people, those whose loved ones are still missing, take notice of such cases not out of hope the trail will lead to a dead body, Dyroff said. Instead, they want to keep hope alive. By finding out that a professed killer's claims are false, they can continue believing their loved one is still alive, she said.
And most of the time, stories such as Barbour's do turn out to be concoctions, retired FBI investigator Keith Lanning told CNN.
"A lot of these individuals, particular some of the adult survivors, have emotional and psychological problems, and a lot of their motivation is to get attention and forgiveness for various problems in their lives," he said.
Some just want to try to cash in on a fragile connection to a case in hopes of working themselves out of trouble with the law, said Dyroff.
Whatever their motivation, it ends up leaving victims hurt all over again, Dyroff said.
"When you can't get any of those pieces to fall into place, it's very hard," she said.
CNN's Matt Smith contributed to this report.