Dee Lynn, 76, was found dead hidden inside a suitcase in her Meridian garage on June 19, 2007.
Prosecutors say Carrie Horsman, 44, pleaded guilty Tuesday to failing to notifying law enforcement or the coroner's office of a death, and also a charge of grand theft.
At the time, Meridian Police investigated the case as a homicide. That was revised to a suspicious death investigation after the coroner's report found no signs of trauma to the body and the toxicology test came back normal.
The coroner said the body was too decomposed to determine a cause of death.
Police arrested Carrie Horsman, 42, in May and charged her with Failure to Report a Death and Grand Theft.
"She was obviously aware of Dee Lynn's death and was purposely concealing that from us," Meridian Deputy Police Chief Tracy Basterrechea said. "We believe at that point that she was in possession of several checks belonging to Dee Lynn."
Horsman also pleaded guilty to stealing $7525 from Lynn.
She faces up to 25 years in prison. Sentencing is scheduled for December 12.
Neighbors who remember the whole ordeal when it happened are hoping this arrest may lead to more answers in this case.
"It's never too late to do the right thing so hopefully she will confess, or tell on who actually did it if she didn't do it," Neighbor Freddy Rosaril said.
Police have not closed the door on a homicide and are hoping someone will come forward with information in the future.