He was caught two years ago this month after a bank robbery in Garner -the day before the SBI lab had connected the five Raleigh murders.
A gun found during the robbery arrest was later determined to be the gun used in all the murders.
Cooper and his attorneys are hoping the judge will keep jurors in his death penalty trial from hearing about confessions he allegedly made to investigators trying to solve the murders.
"He's giving very specific details that would have occurred only had you been there," Raleigh police detective Amanda Salmon said.
Salmon's testimony in court Monday also revealed never released details about the cases.
One was that the robbery and murder at Bobby's Grocery in south Raleigh was captured on surveillance video.
It reveals the robber walks in and immediately shoots and kills Tariq Hussein, then goes for the cash register and steals Hussein's gun.
Testimony also exposes that Cooper allegedly told detectives the murder of Ricky High in October of 2007 was a mistake.
They say he was trying to get back at a gang member who made a comment to his girlfriend, but the gang member ran and High heard Cooper's voice.
"He felt Ricky would know who he was and he felt, at that point, he couldn't let Ricky live," Salmon said.
High, like most of the victims, was shot in the head.
Authorities say some victims were shot multiple times, some in the back of the head -all according to police, so they couldn't identify Cooper.
That includes Leroy Jernigan, whose family members fought back tears as they sat in court Monday.
"He has no feelings," Jernigan's sister Chasity Jernigan said. "He had no remorse. I mean, he's smirking. He's, you know, smiling and to me that's not human."
When ABC11 Eyewitness News interviewed Copper in jail, he didn't confess, but did comment when asked whether he should be considered dangerous.
"(laughs)... I say I think we both know the answer to that don't we," Cooper said.
The hearing will continue Tuesday. The judge's decision on whether to allow the confessions released may be determined when the case goes to trial.