VIGO COUNTY, Ind. (WTWO/WAWV) – Erika Case was found murdered in a West Terre Haute home on September 6, 1998.

She had been stabbed over 30 times in the home she was house sitting.

“When the case was put together back in 1998, it was determined through investigators that two boys came over and basically kind of had a small little get together,” explained Chief of Operations at Vigo County Sheriff’s Department Derek Fell. “A party. So that’s kind of where it began as far as who we looked at as possible suspects.”

For years authorities in Vigo County had no leads, and the case went cold.

In 2013, the Vigo County Sheriff’s Department reopened the case with the help from the TNT show Cold Justice.

“They brought in a couple of their investigators. It was very beneficial because of the fact that you can focus on a case for a period of days,” said Fell. “Whereas in a smaller agency like ours it’s hard because we have constant cases. We have limited staff. So it makes it easy when they bring in their resources to help work the case.”

Authorities zeroed in on Clinton Mackey who was living in Iowa with his wife and children.

“We had went out to Iowa and actually talked to him when Cold Justice was here,” said Fell.

TNT finished their series on the case, but the sheriff’s department was just getting started.

Detectives continued to put the heat on Mackey by speaking with family in Iowa and in Florida.

Eventually, Mackey couldn’t take it anymore.

“He actually came into the police department in Iowa, which is where he lived.” explained Fell. “And he wanted to confess to the murder.”

Mackey was 18 at the time of the murder, 33 when he finally confessed.

He pleaded guilty to voluntary manslaughter in 2015 and was sentenced to 40 years at the New Castle Correctional Facility.

The Indiana Department of Corrections confirmed Mackey died in prison on August 10.

An autopsy revealed the cause of death was asphyxia due to hanging, the matter of death was suicide.

Looking back on the case, Fell says his heart is with Case’s family and friends at this time.

“For basically 21 years now they’ve been robbed of things that you and I and anyone else takes for granted on a daily basis. They don’t sit down at the dinner table and have dinner. No birthdays to celebrate. No family vacations,” he explained. “And nothing is going to bring Erika back. And I don’t think anything is going to ease their pain over the last 21 years. And that’s all because of the decisions, the tragic decisions that Clint Mackey made 21 years ago.”