COLUMBUS, Ind. -- The stepmother of a girl who was fatally stabbed in an apartment spoke with 6News Saturday as police ratcheted up their investigation.

Donna Porter told 6News' Cheryl Jackson that she is tortured as she thinks about the last moments of Chelsea Porter's life.

Chelsea Porter, 14, died of stab wounds in the apartment of a woman she was visiting that she had known for years.

The woman told 6News that Porter stumbled into her bedroom at about 3 a.m. Friday morning, bleeding and dying.

"Every vision I get is how scared she would have been," Donna Porter said. "(It's) your worst nightmare come true."

Donna said Chelsea came to live with her when she was about 4 years old, when Donna married the girl's father.

Porter said the family worked hard to deal with Chelsea's learning disability and other challenges.

"She had speech problems and hearing problems. People made fun of her," Porter said.

Porter said Chelsea was unable to comprehend the kind of violence that took her life.

"She didn't know what was coming. She didn't know things like that could happen at all," Porter said. "She was completely innocent."

Porter said Chelsea loved to laugh and loved horse, but it was another love that put her in the wrong place at the wrong time.

"Chelsea loved babies, and that's why she was there," Porter said.

The woman who loved where Chelsea died has a baby boy that Chelsea loved, Porter said.

"She's gone. She's gone, and there's no bringing her back," Porter said.

Police said Saturday they are interviewing more than one person of interest and that they are working around the clock to solve the case.