The Cuckoo's Calling (Cormoran Strike) by Robert Galbraith

Published under a pseudonym, J. K. Rowling's brilliant debut mystery introduces Detective Cormoran Strike as he investigates a supermodel's suicide in "one of the best books of the year" (USA Today), the first novel in the brilliant series that inspired the acclaimed HBO Max series C.B. Strike. 
 
After losing his leg to a land mine in Afghanistan, Cormoran Strike is barely scraping by as a private investigator. Strike is down to one client, creditors are calling, and after a breakup with his longtime girlfriend, he's living in his office.

Then John Bristow walks through his door with a shocking story: His sister, the legendary supermodel Lula Landry -- known to her friends as the Cuckoo -- famously fell to her death a few months earlier. The police ruled it a suicide, but John refuses to believe that. The case plunges Strike into the world of multimillionaire beauties, rock-star boyfriends, and desperate designers, and it introduces him to every variety of pleasure, enticement, seduction, and delusion known to man.

You may think you know detectives, but you've never met one quite like Strike. You may think you know about the wealthy and famous, but you've never seen them under an investigation like this.