In this case. But if they can tie him to a different murder, he can get the death penalty for that one.
As a sheriff deputy friend of mine says, "This ain't the first time he's been to the rodeo."
They get him on this one in exchange for bargaining away the DP, then seek the DP on one or more of the other murders. AND they can use this confession/conviction as evidence of a similar transaction in the other cases, making it easier to get the DP there.
You can only kill him once, and it seems like this is a target rich environment.
Problem is, this would have been a perfect DP case, with evidence of torture/depraved mind. In the older cases it's going to be harder to pinpoint evidence of torture.
One place to look closely is at the murders of the two elderly hikers in Pisgah Nat’l Forest a couple months ago. Her body was found but her husband’s was not.