Columbus police say they suspect foul play and they're seeking a male "person of interest."
As they continue their investigation, family members and friends of Popovich, 20, of Reynoldsburg, Ohio, are also looking and handing out fliers, among other things.
Sherry Mercurio, a spokesperson for the Columbus police,
She adds, "We developed information that told us that perhaps this could end up becoming a homicide. We don't have physical evidence that tells us that right now, but based on our years of experience, we said at that point it was probably a good point to transition it over to (the) homicide (unit), where they could take the lead and use their expertise."
Popovich's close friend, Tiffany Maynard, tells Syler it's been an "extremely difficult last 13 days."
She stresses that Popovich isn't the type to fake her own disappearance or go off with someone she doesn't know.
"Anyone who knows Julie knows she's extremely responsible," she says. "She wouldn't miss a day of work. The one thing that threw all of us off is she has a dog that she wouldn't leave for four hours to play poker. That she would take the dog with her. So when she didn't come home one night, it was certainly an issue."
Does she fear the worst for Julie?
"To be realistic," Maynard says, "you have to have that in the back of your mind, but it's certainly in the back of our minds. We're all extremely hopeful and are willing to do whatever we have to do to find Julie and get her home safely."
Anyone with information about Julie Popovich's disappearance is asked to call Central Ohio Crime Stoppers at 614-645-TIPS (614-645-8477).