Arguments for Sam Parker's appeal to the Georgia Supreme Court Monday hinged upon evidence gathered in what public defender David Dunn called an illegal search.

Investigators trespassed and gathered evidence that was should have never been allowed to be presented in a trial, Dunn said.

The former Lafayette cop convicted of killing his wife hopes the Georgia Supreme Court gives him a new trial. It's a case that rocked the town of Lafayette starting in 2007 when 911 dispatcher Theresa Parker went missing. In 2009, a jury found her husband, Lafayette police officer Sam Parker, guilty of murder.

Parker is currently serving a life prison sentence for the murder of his wife, but he's maintained his innocence all along. He filed for an appeal immediately following the conviction. It's a lengthy process that comes to a head Monday in Atlanta when his public defender tries to convince a Georgia Supreme Court to grant Parker a new trial.

The 2009 trial gained national attention.

"It was such a mystery. No one knew, and I contend no one to this day really knows what happened to Theresa that day," Public Defender David Dunn said.

But a jury contends he killed her. A year later, a farmer found Theresa's body near the banks of the Chattooga River. While he's been serving a life sentence in prison, his public defender has been working on an appeal.

"I will tell you this to an absolute certainty, I was not convinced at any point by the state's evidence that he killed his wife," Dunn said.

Monday Dunn goes before the Georgia Supreme Court in an effort to get that guilty verdict tossed. The court will give him 20 minutes to prove the first trial was flawed. His biggest argument is the use of evidence deputies seized from Parker's home the day Theresa went missing.

"That was an illegal search and the judge should've suppressed the evidence they obtained," Dunn said.

He's confident a second trial would set Sam Parker free.

"I think we'd have a retrial and we'd win," he said.

Theresa's family says they haven't decided if they'll go to relive the trial Monday or not. Since she was laid to rest, they've shifted their energy toward helping raise awareness about domestic violence.  

"We are just on a mission to have her death not be in vain," Theresa's sister Hilda Wilson said in a 2012 interview with Channel 3.

Sam Parker's convictions are for malice murder, making false statements and violating his oath as a police officer. Prosecutor Leigh Patterson won the case. Monday, she will argue against the appeal before the high court.