She was walking down a street with her headphones on. She was never heard from again.

She was last seen walking down a Fort Lauderdale street the evening of May 20, 2017.

Sophie Reeder, then 15, was last seen on a business surveillance camera casually strolling by with headphones on.

She has not been heard from since.

“Just the not knowing is the worst part,” her mother Nicole Twist told CBS4 soon after Sophie disappeared near the home where she had lived with her father, Patrick Reeder.

Shortly before she went missing, Sophie had been diagnosed with a mental illness and was attending school online.

According to a Facebook post from missing children’s advocacy group Missing Pieces Network, her family fears that she was a victim of human trafficking.

There have been few new leads, but the case has been thrust back into the spotlight.

TV personality John Walsh features the girl on his Investigation Discovery crime show, “In Pursuit with John Walsh,” airing 10 p.m. Wednesday. The series, which costars Walsh’s son Callahan Walsh, has a partnership with the National Center for Missing & Exploited Children.

Walsh knows well about this tragic issue. His 6-year-old son Adam Walsh was abducted on July 27, 1981, during a shopping trip to Sears at the old Hollywood Mall after his mother, Revé Walsh, briefly left him unattended.

Roughly a month later, Adam’s head was discovered in a canal near Vero Beach. In 2008, the case was closed after the murder was pinned on drifter Ottis Toole, who died in prison, convicted of other crimes, in 1996.

Due to the tragedy, Walsh turned his life over to finding criminals, starting “America’s Most Wanted” in 1988.

Anyone with information on Sophie’s whereabouts is asked to call 833-3-PURSUE or submit a tip at www.InPursuitTips.com.

This story was originally published January 23, 2019 at 4:52 PM.