JACKSONVILLE, Fla. -- A crime more than a decade old has been getting attention after the lawyers representing a man convicted of killing his brother's wife claim DNA proves their client does not belong behind bars.

The story began on April 17, 1994, when police investigated the scene of a murder in Mayport where they found the body of Tina Heins. Her 19-year-old brother-in-law Chad Heins was charged with the crime.

More than two years later, Chad Heins went on trial.

"I couldn have done it. I loved her too much," he said on the stand.

On December 13, 1996, the jury visited the crime scene. Seven days later, they found Heins guilty of first-degree murder.

Prosecutors asked for the death penalty, but Heins received a life sentence.

Nine years after Chad Heins' murder trial, he maintains that he didn't kill his pregnant sister-in-law.

Recently, his lawyers announced that new evidence in the case has changed everything.

"I really believe if they had this DNA evidence 12 years ago, Chad never would have gone to prison in the first place," said defense attorney Nina Morrison.

Defense attorney's filed an 89-page motion asking a judge to free Heins based on new evidence. They said during the original trial, jurors never heard that hairs found on Tina Heins' body matched DNA found under her fingernails, and the DNA does not belong to Chad Heins.

"It's of a man, and nobody knows who it is," Morrison said.

"We're not so much contesting the findings. I think it's the significance of the findings that's really open for dispute," said Rich Manei of the state attorney's office.

Mantei said the new DNA testing done on old evidence doesn't prove Chad Heins didn't commit the crime.

Angela Corey, one of the original prosecutors in 1996, said she has looked over the latest defense motion.

"We will fight this motion in court," she said.

The state attorney's office said if it comes to it, they're ready to go to trial again, and that they have already started doing their research.

"(It's) an overwhelming case of both circumstantial and direct evidence," Corey said.

Corey said the defense told jurors Chad Heins was asleep and didn't wake up as someone else brutally stabbed Tina Heins to death. She said jurors didn't buy the story then and they won't buy the story now.

Defense attorney's said the science doesn't lie, and Chad Heins should be a free man.

"He should not be behind bars a minute longer," Morrison said.