Unfortunately, it takes a long time for the characters to put these clues together. Which is symptomatic of the book's problems. The narration is divided between Scarpetta, the three other leads, and a couple of villains. Scarpetta and company are investigating four or so crimes that may or may not be related. They're angry with each other most of the time and don't resolve their differences.
Worst of all, the book jumps from a tense scene where the villain has Scarpetta by the neck to an epilogue where the protagonists are digging up the bodies. In other words, the story's climax happens off-screen (or off-page). If a major work of fiction (Predator is ranked #10 among Amazon's mysteries and thrillers) has ever had this poor an ending, I can't think of it.
The fans seem to agree. On Amazon, 244 of 407 reviewers gave Predator one star. Again, I've never seen a major work of fiction fare this badly.
Some representative comments:
[A]fter a tired plotline about a European "werewolf" which spanned a couple of books, the point of view changed to third person, the story became much more of an ensemble cast with Scarpetta as one of the characters, and everything became permeated by a depressing, unhappy, dreary atmosphere that sucked the happiness out of the characters, and turned them into automatons who did nothing else but work, argue, and deal with death.
It all began to go downhill when "Silence of the Lambs" won all those Oscars and Cornwell decided she wanted a piece of the serial killer pie. The plots became increasingly outlandish, the characters became irritating, and the violence became nauseating. All these trends coalesce in "Predator" and Cornwell gives us the perfect storm of bad suspense fiction.
For more on the subject, see The Best Indian Books.