(Little, Brown)

Any Michael Connelly fan could have predicted that the situation that kick-starts “The Crossing” — the latest Hieronymus “Harry” Bosch novel — isn’t going to end well. I’m not talking about armed robberies, home invasions, rogue cops or shootouts with stone-cold killers, all of which provide some tense moments here. No, I’m talking about the toughest jam Bosch has ever faced: retirement.

At the conclusion of his last outing, “The Burning Room,” Bosch got himself suspended from the Los Angeles Police Department on a trumped-up complaint. Instead of fighting his suspension, which would have entailed months of paperwork, during which time he would have had to live without his salary, Bosch capitulated so that he would be able to pay for his daughter’s college expenses.

In retirement, Bosch has been restoring an old Harley, a hobby that keeps him occupied for maybe 10 minutes a day. As another character remarks, “Retired and relentless are two things that don’t mesh together very well.”

Bosch may be out to pasture as far as the Los Angeles Police Department is concerned, but Connelly is still very much in his prime as a suspense writer. “The Crossing” is a pensive thriller that’s ingeniously constructed and ambitious in scope. Indeed, it’s even something of a twofer: The hero of another Connelly series, Mickey Haller (a.k.a. “The Lincoln Lawyer”), hires Bosch at the outset to work as a private investigator. Haller, who is Bosch’s half-brother, is a criminal defense attorney. He wants Bosch to find evidence to clear his client of the murder of a woman named Lexi Parks — the wife of a sheriff’s deputy — found bludgeoned to death in her bed. That’ll be difficult given that DNA evidence at the scene points to Haller’s client. Even more difficult to overturn are Bosch’s own qualms about the job. Here’s his initial response to Haller’s offer:

“ ‘I work a case for you — not just you, any defense lawyer — and it’ll undo everything I did with the badge.’

In author Michael Connelly’s latest Bosch novel, Harry tries out a new gig investigating for a defense lawyer. (Mark DeLong Photography)

“Haller looked incredulous.

“ ‘Come on. It’s a case. It’s not — ’

“ ‘Everything. You know what they call a guy who switches sides in homicide? They call him a Jane Fonda, as in hanging with the North Vietnamese. You get it? It’s crossing to the dark side.’ ”

But, cross Bosch does. He’s motivated a bit by money, a bit by boredom and, in the best hard-boiled tradition, a lot by a desire to get at the truth of the crime. By the way, the position is available because Haller’s regular investigator, Dennis “Cisco” Wojciechowski, is out on medical leave after being knocked off his motorcycle in a suspicious hit-and-run . Cisco was lucky to crawl away from the accident, but other people connected with the Parks case soon begin turning up dead.

Bosch’s investigations take him all over his beloved L.A. and beyond, from swank watering holes to hot-sheet motel rooms. All the while, Bosch is being tracked by killers and dogged by obscenity-laced phone calls from irate former Los Angeles police colleagues who’ve learned of his defection to the enemy country of criminal defense.

As always with a Bosch novel, the delight is in these “inside police” details. When Bosch begins reading the police file or so-called “murder book” on the Parks case, he studies it as closely as a rabbi studies the Talmud:

“He knew every trick there was when it came to planting obfuscation and misdirection in a murder book. . . . It had been his routine practice back in the day to redact words in reports . . . to intermittently remove the toner cartridge from the squad room photocopier so that pages and pages of the documents he was turning over were printed so lightly they were impossible or at least headache-inducing to read.”

Now, Bosch finds himself perched, uneasily, on the other side of the investigation, searching the files for police errors or coverups that might not be evident to an investigator without all his years of experience. What Bosch does discover in “The Crossing” is a vile conspiracy and a new vocation as an independent investigator that should keep him busy — and Connelly fans happy — for years to come.

Corrigan, who is the book critic for the NPR program “Fresh Air,” teaches literature at Georgetown University.

The Crossing

By Michael Connelly

Little, Brown. 388 pp. $28