Sharon Zolper is one of the regulars from the local pool of talent at Penobscot Theatre. She has played Lady MacDuff in “Macbeth,” M’Lynn in “Steel Magnolias” and several other showcase roles. But none of them has been as convincing as her work in the current Penobscot show, “Dial M for Murder,” which opened over the weekend and runs through May 26.

Statuesque and honey-blond, Zolper has the won’t-quit elegance of an old-time movie star. With her hair carefully wound in stylish twists and chic costumes, she could have stepped right out of a Hitchcock thriller. But it’s not only the right look that Zolper brings to the role of Margot Wendice. She shows an intelligent, discerning woman who can defend herself ably when an unexpected late-night visitor (played villainously by Robert Libbey) tries to strangle her with a scarf.

The murder scene is the best moment of Frederick Knott’s well-known 1952 British thriller, which Alfred Hitchcock, indeed, transformed into a successful film. Director Mark Torres shows his stuff as a stage-combat choreographer with this scene, which could be rather embarrassing theatrically. Instead, it’s suspenseful and energetic. There’s a wrestle, a wrangle, screams, thuds, jabs and punches. And, of course, a pair of scissors.

No secrets will be divulged here about the outcome, although it seems most people know it anyway. Suffice it to say that Zolper’s Margot can take care of herself when push comes to shove.

Plot elements that lead up to this scene include an affair Margot is having with American TV writer Max Halliday, played with friendliness by guest actor Blair Hundertmark. Margot’s husband, a has-been tennis champ named Tony, finds out about the affair and secretly uses it to blackmail an ex-con into murdering Margot. Then Tony can collect a sizable bundle of dough from the life insurance.

John Rahal Sarrouf plays Tony and offers one of the most problematic performances of the show. As with Zolper, Sarrouf has the looks that make appearances convincing but doesn’t have any of the subtleties of an evil genius. His plastic smile goes on too long and it’s difficult to stay interested in his lines because they are spoken so slowly and often with garbled pronunciation. Sarrouf is just a little too smug in the role to be convincing.

As the police inspector, Davidson Kane is nearly cartoonish in a cowboy-size fedora and trench coat. This is not Kane’s best performance, but he’s intimidating and slippery as a good cop should be. Shawn Johnson, in a bit part, plays his sidekick.

Shadowy lighting by guest designer Lynne Chase and old jazz tunes played during blackouts are a smashing addition to the drama of the story. Ginger Phelps and Mickey Bliss show some real class with their black-and-white array of costumes, which perfectly blend with Jay S. Skriletz’s black-and-white set of an upscale London flat.

In previews, the show moved at a tiringly slow pace. One hopes that this will change with time. The script relies on lots of details, so it vitally needs that persistent pace of contemporary British shows. Even in previews, however, when the timing picked up, the audience got caught in the suspense and the acting was at its slickest best. That’s what it’s all about and when it works, it works murderously well.

“Dial M for Murder” will be performed 7 p.m. Thursday, 8 p.m. Friday, 5 and 8:30 p.m. Saturday and 2 p.m. Sunday through May 26 at Penobscot Theatre. For tickets, call 942-3333.