Spring Heeled Jack was a suspect in popular imagination at the time.
The best suspect so far is the demented Jew, Kosminsky, who was quietly banged up in a madhouse(after that, the killings seemed to stop.) The very real danger of a pogrom made the authorities reluctant to place the blame on him. Evidence is scanty either way, but detectives liked him for the crimes(police slang),at the time.
Of course, they also liked M.J. Druitt, who had the all important property of being dead, and thus, a perfect patsy.
Victorian law enforcement was primitive, and the Ripper was the first serial murderer to be recognised as such. Hysteria was the usual response to a spectacular crime, and the police were too often willing to offer up a human sacrifice to quieten the mob.
Go read "The Maul and the Pear Tree" for an overview. Then look up the Wylie Hoffert murders to see how little things had changed by the 60's.
Justice is a slippery concept, but revenge is well understood. For a long time the idea that''somebody has to pay'' was the gold standard for authority, and the pitchforks and torches approach was common-thus we got lynch law, mass punishment and the frame up.
Now you have a clue as to why I'm not in law enforcement any more.