He's seeking a new trial.
In April 2010, a jury found Cooper, 34, guilty in a string of five murders. Prosecutors said he shot Osama "Samuel" Haj-Hussein, LeRoy Jernigan, Timothy David Barnwell, Ricky High and Tariq Hussain to cover up a series of robberies throughout the Triangle in 2006 and 2007.
Prosecutors said Cooper murdered to prevent people from identifying him. It wasn't until Cooper was arrested in November 2007 after a chase following a bank robbery in Garner that police found a 9mm pistol that linked him to the killings.
During the trial, jurors heard muffled audio of Cooper confessing to investigators that was recorded November 24, 2007. On the tape, Cooper admitted to all the murders, including the death of 48-year-old Ricky High, who according to Cooper, was in the wrong place at the wrong time.
At the trial, Cooper's lawyers did not dispute that Cooper was behind the killings, but they argued he had a diminished mental capacity because of posttraumatic stress disorder - that he was programmed to kill by a father so abusive - both physically and sexually - that Cooper became mentally unstable.
The audio recording of his confession appeared to hurt that defense because it suggested premeditation. At one point in the confession, Cooper told investigators about the murder of Timothy Barnwell.
"I'm a good shot bro," he said. "I believe I shot him from the balcony."
"After you shot him, what did you do," investigators asked.
"I used a towel to clean out inside the place," Cooper replied.
He also described murdering 40-year-old Leroy Jernigan in July 2006.
"I just shot a dude, that's all," Cooper said.
But at the hearing Thursday before the NC Court of Appeals, Cooper's lawyer said investigators exploited Cooper's relationship with his father to get the confession.
"Sammy confessed because police arrested his dad and he has a very strong attachment to his dad - psychologists say he had a pathological attachment to his dad," explained attorney Mark Montgomery. "The police knew that and exploited that by arresting his dad and parading his dad in front of Sammy's cell and Sammy pounds on the window and says 'I'll confess to everything.'"
Montgomery argued the tactic violated Cooper's constitutional rights.
"The trial court accepted the police officers testimony that they didn't know his attachment and did not exploit his weakness," said Montgomery.
Montgomery also said Cooper was living with his parents at the time he was arrested and his father - a convicted felon - dumped a gun in a bucket of bleach and his mother took a large amount of money to a relative's house. Montgomery said they both could have been charged with or without Cooper's confession.
But prosecutors said investigators never promised they'd release Cooper's father if his confessed. Instead, Cooper said he'd talk if they let his father go.
Montgomery also said Cooper asked for an attorney during another taped interview, but that recording was lost or destroyed.
"We've argued the murder convictions should be set aside and that he should be re-tried without the use of the confession," said Montgomery.
At his 2010 trial, the jury deliberated for three days, but ultimately decided against a death sentence. Cooper is currently serving multiple life terms. His lawyer said his ultimate goal is to get Cooper a shorter sentence.
When asked Thursday about the families of the victims, Montgomery said: "I feel for the families' loss, but my job is to protect the Constitution through protecting my client."