Police say a 32-year-old Emily Graham was selling the ring on Craigslist for $19,000 when she got a message from a potential buyer who said he was interested, but wanted to see the ring in person.
She was in Wisconsin, he was in Missouri.
The man bought Graham a plane ticket and flew her to St. Louis. Shortly after she got off the plane, she realized something was wrong.
A driver picked her up, but instead of taking her to a jewelry store, he took her to a deserted area. A second man opened the car door and pointed a gun.
"I said, 'can I just have my ID?' And then he hit me over the head and said, 'shut up you stupid b****,'" Graham said.
Police are now tracing the credit card the thieves used to buy her airline ticket and fly her all the way across the country so they could rob her.