Well, after reading the N&O article, it isn't perfectly clear whether he's actually a sworn peace officer or not, but it is clear that he works for the DA's office as an investigator. According to the article, Wilson would have been a certified peace officer at least in the 70s when he worked as a public safety officer for six years. If he arrested Mostafa on the outstanding warrant himself, then he must be sworn, which would mean that through whatever mechanism in NC peace officer standards is specified, he managed to keep his peace officer's training certificate current. Some DA's offices hire non-sworn investigative personnel along with sworn personnel, but such a person would not be able to serve an out-of-custody arrest warrant. I don't remember now if Wilson served the warrant or if one of the DPD officers served it, but that would be a way to know if he's an investigator with full police powers. I suspect he's sworn, but I can't say for sure based on the skeletal information provided in the story. From what I've seen of NC law and procedures and the prevailing laxity there, I doubt that it would be difficult to meet the standards or to be reinstated if a prosecutor signed the right papers to make it happen.
What's amazing to me is that Wilson is the only investigator on the DA's payroll. For a county that size and the number of ADAs in the office, it's bizarre.
Another thing, since Nifong gave him the job, hiring him out of mothballs as he did, Wilson is likely to be extremely loyal to Nifong and will do what he can to protect him. It would also be interesting to know if Wilson and Nifong had a personal relationship before Nifong hired him, or if Wilson is one of those kinds of local guys with a lot of street cred in the legal community for getting the job done or, more likely, being the go-to guy to get something done under the radar.
Thx.