Sadly,,if it turned out to be the guy in question,,and it was him carrying a child,,then that child would no longer have been alive at the time. A 6ft 2 chap would have no trouble in keeping a small child quiet.
Again,,it's possible,that if by any chance it was this guy,,then he would clearly have been under the influence of heroin as he strolled along carrying a dead child. He was in no hurry.
Up to now,,we haven't been shown his pic,,against those of the e-fits that were shown. Maybe that's where the police got their lead from,I don't know.
So far,,it is speculation,and the McCanns' don't appear to be perturbed by this latest news.