The mother wrote a letter to her daughter 20 years after she went missing: "Praying that wherever you are, you are safe and happy."
Twenty years ago, Jonnie Carter spoke to her 11-year-old child, Bethany Markowski, over the phone and told her she loved her before ending what became the very last conversation she had with her daughter before she vanished without a trace.
"She said 'I love you,' and I said 'I love you, too,'" the mother said as she recalled their last conversation.
At the time, Bethany was with her father, Larry Markowski, who was going through a divorce with Jonnie but had court-ordered visitation rights to see their daughter during the weekend, according to WREG.
According to Larry's version of what happened on March 4, 2001, he was taking a nap in his car while Bethany went alone inside the Old Hickory Mall in Jackson, Tennessee. Upon seeing that Bethany hadn't come back in a couple of hours, Larry went looking for her inside the mall but failed to find her anywhere. What is strange is that investigators found no proof of Bethany going inside or leaving the mall that day.
Although Larry was not named as a suspect, "he's not been very cooperative, and he has not participated in the investigation at all," Cathy Ferguson, a special agent with the Tennessee Bureau of Investigation, told PEOPLE.
For two decades since Bethany was reported missing, her mother has not stopped working to find her and still believes she will someday reunite with her daughter, who would be 31 years old now.
"She's been gone way longer than I had her," Jonnie said. "The pain and the hurt and the memories... that's a tough one on parents and siblings and family members. Not only do you lose the person—after a while you start losing the memory of them. How they look. How they smell... That's hard. It's really hard."
Still determined to find her daughter, the mother added, "I guess the thing that keeps me going is the fact that I'm her mom. If I stop, everybody stops. Not looking for Bethany is just not an option."
Thousands of tips were received by the police since Bethany went missing, and even though nothing concrete came out of them, Jonnie says she won't stop searching.
"We’re still looking for her. We are not giving up. No mother ever wants to think that their child’s not alive -- especially without any proof. But there are days when I question that myself," the mother said, as quoted by NBC News.
Over the years, Jonnie advocated to have lawmakers establish March 4 as "Tennessee Missing Children's Day" and the bill was passed in the state legislature, according to WBIR.
With 20 years having passed since her daughter went missing, Jonnie wrote a letter to Bethany on the National Center for Missing & Exploited Children blog and said: "We will never give up on finding you, loving you and praying that wherever you are, you are safe and happy."
Anyone with information on the disappearance of Bethany Markowski, please call NCMEC at 1-800-THE-LOST.