My favorite candidate for the Ripper is one you can find hiding in plain sight in the case files. He was the first person known to be at the scene of the first murder, a man named Charles Cross.
I suspect him because:
* A police constable passed the scene of the crime not 30 minutes before he “found the body” and there was nothing there, so we know Cross was at the scene within a short frame of time as when the Ripper was there.
* He didn’t immediate report the body to police upon finding it. Instead, another man was coming down the street, and Cross called him over and said “look at this, there’s a woman over here”. Had Cross just discovered the body? Or was he the killer who came up with this “discovered the body” story when he was surprised by a passerby?
* This victim was not mutilated much at all compared to the other victims. This could be due to the killer progressively getting more brutal, or it could be because the killer was interrupted, for example, when a passerby turned on to the street and surprised him.
* He left the scene, apparently he “didn’t want to be late for work”. Him and the passerby did report the body to police after they ran into a constable. But I’m not so sure he would have done that if the passerby hadn’t been walking along with him. At that point, if he had been the killer, he had no choice but to go along with the ruse.
* Another constable discovered the body on his own before those two reported it. Because of this, there was confusion about who actually discovered the body, because a lot of newspapers reported that it was first discovered by a constable. Thus, in the confusion, not a lot of attention was paid by researchers to Cross until recently.
There are other interesting points about the guy too if you delve into his background. For example, he regularly walked to and from work late at night or early in the morning through the neighborhoods where the murders happened, right at the times when they were happening. He also wore an apron, and many witnesses who reported seeing the presumed killer said he wore an apron.