In February 2005, when a million Internet voyeurs were poring over the contents of Paris Hilton’s hacked Sidekick with the same intensity that earlier generations applied to Bob Dylan’s lyrics or Richard Nixon’s Watergate tapes, one name piqued the attention of Hollywood journalist Mark Ebner: Darnell Ryley.

“In a field of famous names, it’s the ones you don’t know who signify the real story,” Ebner writes in his new book Six Degrees of Paris Hilton. Initially, Ebner didn’t act on his interest—he was working for the nation’s leading supermarket tabloid at the time, and, apparently, enquiring minds are mostly interested in names with which they’re already familiar. But a few months later, when Radar magazine assigned Ebner a story about a trial involving Girls Gone Wild founder Joe Francis, that unknown name—morphed slightly because Paris was no longer responsible for spelling it—popped up again.

Darnell Riley, Ebner learned, had been accused of breaking into Francis’ home and holding him at gunpoint for six hours while forcing him to make a humiliating videotape involving a pink vibrator and some ironic softcore porn-mogul nudity. Then, Riley locked Francis in the trunk of a car, stole cash and other valuables from his home and, over the next several months, attempted to extort $500,000 from him in return for keeping the tape private.

How did Riley, convicted of a double homicide committed during a jewelry-store heist when he was just 15, get into Paris Hilton’s Sidekick? What does it say about our culture when model-actress-heiresses openly consort, or at least exchange chummy text messages, with kidnapper-burglar-extortionists, other than the fact that we’re all multi-hyphenate overachievers now? These are the questions Ebner sets out to explore in Six Degrees.

Skeptical, tenacious and carrying on the great tradition of Tinseltown noir, Ebner takes his investigative efforts far beyond the rope lines of Hollywood Boulevard, uncovering enough ecstasy kingpins, larcenous lingerie models and hard-boiled Russian bail-bondsmen to populate the fever dreams of James Ellroy, Bruce Wagner and the ghost of Raymond Chandler for a long while.

In Riley, Ebner has a pretty good star to build around—he’s movie-star handsome and unusually intelligent and has a knack for coming up with crazy criminal gambits that would do Paulie Walnuts proud. On one occasion, for example, he pretended to get electrocuted in the shower at Stevie Wonder’s guest house in an effort to extract money from the singer.

As Ebner documents how Riley made his way from California Youth Authority prisons to Paris Hilton’s Sidekick, however, Riley never acquires the depth of, say, a Tony Soprano—someone whose fate, good or bad, you care about. Ebner offers Riley many opportunities to explain his choices, but he provides little illumination. Instead, Riley spends a lot of time insisting that he’s no worse than white-collar criminals like Ken Lay or Scooter Libby. He spends a lot of time extolling his criminal expertise. But we never learn much about why a 15-year-old A student living a seemingly stable life ends up robbing a jewelry store and killing two people in the process.

In addition, while Six Degrees offers plenty of convincing lowlife vérité, it never achieves any narrative momentum. There’s no sense of escalating drama, no real struggle for redemption, nor even the thrills that come with trying to pull off a really big score. Instead, we get a series of well-written, solidly reported anecdotes about sleazy party people who don’t seem all that fascinating. For his part, Ebner seems largely uninterested in evoking anything more than a knowing sense of disgusted bemusement at the sins and follies of these people, and consequently, he rarely does.