You can understand why the Bucks County Playhouse, wanting to do a murder mystery, found the fiendish, intricate plot of Dial M for Murder by Frederick Knott such an exciting prospect. At the same time, it is puzzling that its production did not take a deeper interest in the characters.

Make no mistake, this is a gripping yarn. Like a Russian nesting doll, you solve one mystery only to find another lurking beneath. Though everyone knows Dial M from the Alfred Hitchcock/Grace Kelly movie, it is easy to spoil a suspense thriller. Yet, to make a point, a few elliptical references are in order.

In a nutshell, there is a disconnect in the past and present lives of some characters. Two lovers, Margot (Olivia Gilliatt) and Max (Clifton Duncan) meet to discuss the enduring consequences of their burned-out affair. Though necessary to set the story, old flames still have embers. But not here, not a spark.

The divide between past action and the stage present becomes a gulf when Tony (J.D. Taylor) enters the scene. He gulls an old Cambridge chum, Mr. Thompson (Grant Harrison), luring him to his apartment. We soon learn Tony spent a full year stalking Thompson’s every move.

Taylor starts off well, nonchalantly wiping fingerprints off wineglass stems; you expect Tony to luxuriate in his cunning. But as he closes in on the “mark,” Tony grows gleeful, starts to hop about like a rabbit. It is difficult to imagine this Tony spending a year in disciplined, painstaking surveillance. (And, remember, the big game in Dial M has not even begun).

Director Mike Donahue is so enraptured by Knott’s clever plot he sometimes loses a sense of continuous character and risks turning actors into implausible plot bearers. Suspense thrillers also work as oblique morality tales; you feel a dull disquiet that the show may prove too off-putting to let you satisfy primal, righteous vengeance.

Unease is muted with atmospheric stagecraft. Anna Louizos’ scenic design is not quite period (London, 1952) but spacey with graphic, perfectly placed exits. There are 15-second “beats” of semi-darkness (wish they were longer) when the apartment becomes a spooky character (kudos to light designer Scott Zielinski).

Broadway’s Graeme Malcolm is sterling as mustachioed Inspector Hubbard. You never know whether the imposing policeman is fooled or fooling. In the end, Dial M holds you in suspense, even oddly humors with irony and surprise revelations (some drew audience laughter). Still, you wish the Bucks production were not so easily distracted by the surface dazzle of Knott’s crafty scenario.

THEATER REVIEW

Dial M for Murder

Through June 15 at Bucks County Playhouse, 70 S. Main St., New Hope. Tickets: $55-$60. Information: 215-862-2121, or info@bcptheater.org