Emily Wood was stabbed by a policeman in a 'delicate' part of her anatomy.

I could believe a murderer ran round with a bloodied cloth, for over an hour, on a journey from Mitre Square to Goulston Street that'd take ten minutes! Why would he stay in the vicinity? With a double murder having taken place, a murderer would want to flee. But no, he hangs about. He holds the garment for over an hour and dumps it in a darkened doorway, complete with chalked message, mere minutes from a savage murder.
Or, I could believe someone left Mitre Square and had to log on at 2 am and get to his beat. That beat encompassing Goulston Street. At 2.20 Detective Halse states he didn't see Constable Long on  patrol at Goulston. At 2.55 Constable Long states he notices a rag on a grubby, rubbish strewn, London Street. It draws his attention. Why? He doesn't know, at this stage, apparently, of any murder having been committed.
This constable was sacked the day after the murder of Alice McKenzie in July 1889. The American press reported that a policeman should be questioned. The English papers didn't print of a policeman's presence at the murder scene.
Emily Wood was stabbed by a policeman in a 'delicate' part of her anatomy. She was granted a full line up of the Metropolitan police, over two hundred officers, but she couldn't identify her attacker even though she'd seen her assailant on numerous occasions, on his beat, prior to her assault. All the officers adjacent to her assault were fair. Her attacker sported a dark moustache.