A husband and wife were living in fear during the four weeks accused "Killer Grandma" Lois Riess was on the run.
Tess Koster believes she could have been another Riess victim.
"It might have been me," she told Inside Edition.
Tess and Rod Koster were good friends with Riess and her husband, Dave, in Minnesota.
"Never seen 'em argue ever," Rod Koster said. "They were a perfect couple, happy all the time. No one could believe it."
"We always chatted with her at the post office or the grocery store," Tess added.
The Kosters were vacationing in Florida, where they own several rental homes, when they heard that Riess was suspected of fatally shooting her husband and taking off with $11,000 to finance her gambling addiction.
"We were very shocked," Rod said.
Tess says she was cleaning out the garage in Fort Myers Beach when, out of nowhere, Lois Riess appeared.
“I was just in shock," she said. "Our eyes met. I said to myself, ‘Lois Riess is in my driveway. What in the world is she doing here? This is scary.' Well, she turned, put her head down, shook her head and said, 'Wrong house, wrong house.' And quick[ly] got in her car and drove away."
Given that she and Riess look similar, Tess was anxious about what she thinks Riess was doing there.
"Well, that's the scary thought," she said. "So did she want to move into one of our many houses? She knew I was there. Maybe she wanted to steal my identity."
Just three days later, Riess allegedly murdered a look-alike she met in a restaurant, and assumed the dead woman's identity.
The victim lived a block from the Koster’s home.
After the murder, Tess believed Riess wanted to come after her next.
“I couldn't eat," Tess said. "I was shaken, it was unbelievable. I was waiting for her to get caught because I was in fear she would return."
After a nationwide hunt, Riess was caught some 1,500 miles away, in South Padre Island, Texas, near the Mexican border.
"I myself hope she never gets out of jail," Tess added.
Riess is expected to be extradited for Florida, where she will face the first of two trials.