BATON ROUGE - A woman who pleaded guilty to manslaughter in exchange for leniency tied to the killing of Gary Kergan in 1984 claimed the sentence she received was illegal and asked a court to correct it.

Things took an interesting twist when Leila Mulla withdrew her request this month.

District Attorney Hillar Moore said that was a smart move.

"We could have tried her for murder," Moore said. "We think the agreement we made was fair. She could have received a lot more, and I guess she had buyer's remorse."

As part of the plea in 2014, Mulla received 30 years for manslaughter and armed robbery. She was ordered to serve at least 85-percent of it and testify against Ronald Dunnagan. Dunnagan was convicted of second-degree murder in 2015 following her testimony and is serving a life sentence.

Mulla claimed her sentence was illegal and her case was set to be heard on April 17.

"This is somewhat unusual for us," Moore said. "It was clear in these circumstances. We were scratching our head."

Moore said what she did is very rare, agreeing to plea out to a crime where her sentence is spelled out and then claiming the sentence was illegal.

Mulla and Dunnagan are both serving time for the killing of Gary Kergan. Kergan was a businessman, and prosecutors said he was last seen on Byron Street in Baton Rouge. Investigators found Kergan's blood in a car that was found in Metairie, but there was never enough to formally charge Dunnagan with murder. The case went cold until DNA tests provided new information bringing the duo to justice. Kergan's body was never found.

In 2014, his family told us they felt a sense of relief that justice had finally been served.

"It feels amazing to have some closure for the case and to have some justice," said Wade Kergan, Gary's son.

"I've been mad for 30 years," said Ted Kergan, Gary's brother. "Now, I'm angry she took my best friend from me."