I think that cop was Sgt. John Shelton, whose April 9 supplemental report is an attachment to Cheshire's motion. He was talking to his watch commander and was overheard by Durham officer Christopher Day, who reported the "20 guys raped her" comment.
The Herald-Sun article that mentions City Manager Patrick Baker's comments on Shelton is no longer online. Damn it!
I thought Chris Day was with Duke police, not Durham.
Anyway, it's obvious Shelton didn't believe Mangum and was probing her story and that's why she didn't want to talk to him.