Police are still investigating the incident and would not comment if the circumstances surrounding Lueth’s disappearance are suspicious.

“The case is still a missing person until we’ve conducted interviews with family and friends,” said State Police Sgt. Kevin Mark.

But Lueth’s sister, Elizabeth Crum, said she fears the case will not end well.

“We are all extremely, extremely worried. We fear the worst because she was doing so well, and she was so cheerful,” Crum said. “There’s just no way that she took off.”

Lueth was last seen by her friend Rick Stilgenbauer, who has subleased the apartment below her for the past five months. She recently broke up with her boyfriend, who had lived with her. He moved out of the apartment they shared between Nov. 6 and 11, Stilgenbauer said.

“She was dealing with everything how she always does — confidently and soundly,” he said. “She’s a very strong-headed woman, she takes care of business.”

Lueth and Stilgenbauer talked in his kitchen Nov. 11 between 5:30 and 6 p.m., after Lueth returned from class at MSU. She was concerned because her ex-boyfriend moved out and her rent would increase. She was planning to sell her truck and start working as a waitress to pay her bills, Stilgenbauer said.

“She was hopeful, sound, planning for the future,” he said.

After Lueth left his apartment, Stilgenbauer did not hear anything from her upstairs apartment.

“I didn’t hear anyone come back in or out, I never heard anyone leave after that. It was all very quiet,” he said.

Stilgenbauer and Lueth’s father, Roy Lueth, both called Krista Lueth on Nov. 12, but her phone went directly to voicemail.

“I’m in contact with Krista all the time,” her father said.

But when none of Krista Lueth’s friends or family could reach her, they were worried, Stilgenbauer said.

Roy Lueth drove to his daughter’s home Friday to look around and said her cat was alone in the apartment.

“She’d never leave her cat if she went anywhere,” he said.

Roy Lueth said he did not want to speculate about the disappearance.

“All we know at this point in time is that she’s missing, and has been since Tuesday,” her father said.

As the investigation moves forward, Krista Lueth’s family and friends are looking for answers.

“It’s a double-edged sword – as much as you want to know, you fear hearing,” Crum said. “You want answers, but they’re probably going to be answers we don’t want.”

Krista Lueth is 5 feet, 4 inches tall and weighs 125 pounds. She has brown hair and blue eyes, police said.

Anyone who has seen her or has any information is asked to contact the Michigan State Police at (517) 322-1907.