Elmore Leonard has long had an irresistible formula for his grit-and-polish crime novels: flawed heroes, strong women, rich or powerful people who abuse their privilege, reasonably clever mob bosses, and not-so-swift crooks - all entangled in stories that are set (at least in part) in Detroit or South Florida, and that undergo plot twists that are surprising yet plausible.

Leonard has rarely been formulaic, though. While using similar pieces, he has wrapped them in a special ability to conceive stories that seem effortlessly real, without requiring even the slightest suspension of disbelief. And he's done it so consistently that readers have come to count on it.

That's why his 36th novel is such a keen disappointment. Coming on the heels of the leaden "Be Cool," his 1999 follow-up to "Get Shorty," "Pagan Babies" raises the awful possibility that Leonard's deep, deep well may be running dry.

In the flawed-hero role this time is Father Terry Dunn, who is somewhat casually ministering to local Rwandans in the wake of the Tutsi-Hutu genocide. Only weeks before the violence began, he had arrived in Rwanda to help his uncle, Father Toreki, tend his flock of 40 years.

Toreki was hospitalized in Kigali when the killing started. He asked Dunn to return to the countryside and bring the Tutsis into his church, because it had always been a place of safety. Dunn did so, with horrible results. Murderous Hutus burst in and began hacking their victims while Dunn stood by, unable to stop it. The memory left a scar on his soul he has been unable to salve, in part because some of the killers lived in his village, even came to him for confession.

When word comes one day that his mother has died, Father Dunn decides, on the spot, to return home - not for the funeral, which he'll miss, but for good; it's almost as if she had been why he left Detroit in the first place. But before he goes, he takes a stab at meting out some of the justice he has seen denied.

Playing the role of the strong woman is Debbie Dewey, who worked as an investigator for Dunn's lawyer-brother before she was sent to prison for running down Randy, a former boyfriend who didn't just swindle her, but even sneered in her face when she found out. Upon her release, she returns to Detroit to pursue two plans she hatched in prison: to break into stand-up comedy, and to get her money back from Randy. (He is the dishonest rich guy, having come out of a divorce with a restaurant to call his own.) The first night she performs, the Dunn brothers are in the audience, and afterward, Terry and Debbie realize their affinity for each other, and begin to see how they can help each other.

Leonard rolls out these back stories over the first hundred pages or so in a pedestrian way, though there are still traces of his uniqueness. He has always had a good ear for patois, for example, and the ability to say it back in print: "Bless me, Fatha, for I have sin. I kill seven people that time I'm still a boy."

And especially for a septuagenarian, Leonard speaks the cultural lingo; in just the first few pages, while the setting is still Africa, he mixes in references to Nine Inch Nails and Ziggy Marley and the Melody Makers. He even finds room for the Stone Coyotes, the rock band that played a central role in "Be Cool."

These touches are proof that he is still Elmore Leonard, but there's enough conflicting evidence for consternation. The Mutt, for example, the leading not-too-swift crook, is a mere caricature when put up against, say, Clement Mansell of "City Primeval," or either Bo Catlett or Ray Bones of "Get Shorty." Fumbled foreshadowing telegraphs what used to jump out as delightful surprise.

In "Pagan Babies," events don't unfold so much as arrive, one after another, until it's over, and one is left with the empty feeling of having read just another story, instead of the thrill and amusement that used to close out an Elmore Leonard special.