Secondly, it's widely considered to be the first documented serial killer case - although this in isn't true. Jack, however, generated a boatload of newsprint, and the image of a demented vivisectionist stalking Whitechapel for unlucky whores took hold.
More particularly, though, it probably is the first case to involve criminal profiling. In the late 1800's, forensic psychiatry didn't exist. Forensics of any kind, crime scene analysis, was primitive. Preserving the chain of evidence wasn't even on the radar. But in the Ripper case, a police surgeon speculated the killer was a
solitary, subject to periodic attacks of erotic mania, a "brooding condition of the mind." In other words, they were taking a stab (no pun intended) at ascribing motive. Jack wasn't simply possessed by evil spirits, he was diseased, as it's commonly understood. Mentally ill. Not an attempt to excuse his crimes, it was a means to an end. If they could isolate the Ripper's logic, they might identify him.
A couple of recent mystery thrillers explore this dynamic, David Morrell's MURDER AS A FINE ART (and its sequel, INSPECTOR OF THE DEAD), and Stephen Hunter's I, RIPPER. Morrell's book isn't about the Whitechapel killings, but a guy mimicking the Ratcliffe Highway murders, which took place seventy-odd years before the Ripper. Hunter's book, as you can tell from the title, is very much about Jack.
It's interesting that two not entirely dissimilar writers have both chosen to do historicals, and Victorian era historicals, at that. I understand the attraction. It's also interesting that both Hunter and Morrell come at it from a somewhat similar perspective. Not a modern one, mind. There's nothing a-historical or anachronistic about their approach. But the period they've chosen is one of huge impending change. The coming of rail travel, say, the Industrial Revolution in full cry. Income disparity, the crushing burden of poverty, the displacement of populations and the rise of dense urban environments. All of this contributes to the rise of a phenomenon like the Ripper. And what the two writers both do, entirely convincingly, is to work out how you'd look for a killer's footprint, the shadow he casts. This is forensic science before it had a name. Reading the runes, or bottling smoke.
When we talk of Dickensian squalor, it's really a kind of shorthand, and an avoidance mechanism. It's hard for us to imagine how squalid and brutish life in the London slums actually was, in Victorian times. Social inequities were extreme, and the Ripper became a metaphor - a gentleman, it was said, preying on the weakest of the underclass. Jack embodies a nameless dread, an entire ruling class of predator. He prefigures, not the Ted Bundys of this world, but gangster capitalism. He represents a stacked deck.
Why was he never caught? Police incompetence, for openers. They weren't equipped to deal with somebody like Jack. Yes, he was a pattern killer, and there was method, and opportunity, and most importantly, repetition, but the cops never established his template, and he slipped the noose. Then again, there's the more sinister theory that Jack was a member of the Establishment, some go so far as to say a collateral cousin of the Royal Family, and a scandal had to be prevented. Because we have the lingering question of why the murders stopped. Maybe they found the guy, but his social position protected him, so instead of going for a short dance on a stiff rope, he wound up in the booby hatch. Which might go some way toward explaining why Jack has such a long shelf life. He eludes us. Not simply because it's the most studied of cold cases, and unresolved even today, but because he himself seems written in water.
Not so, his victims, In death, they have a disturbing physicality, exposed to the naked eye. Mary Jane Kelly was the last of the five, and a police photograph exists, the disemboweled girl lying in her bloody sheets. You can find the picture at the link below, but I won't post it here.