A MURDER IS ANNOUNCED -- At the Olney through June 22.

Agatha Christie and the Olney Theater have been keeping company for so many years they fit like hand in glove, but they're having a bit of a misunderstanding over "A Murder Is Announced."

Christie created her own genre, and her followers must accept her somewhat mechanical and arbitrary method. Most Christie characters are not motivated from within so much as pushed about to suit the author's rather eccentric requirements. Her admirers eventually come to treasure this straightforward personnel policy, but it's damnably difficult to make such characters more than talking dolls onstage.

The Olney Christie, as usual, is vintage, and the cast, as usual, is accomplished. The plot twists and doubles back quickly and outrageously, as the devious Dame Agatha always delighted to do in her Miss Marple mysteries. Nothing is as it seems.

Yet somehow director Leo Brady, for all his long experience at putting together the Olney's annual Christie fest, has not been able to impose a consistent tone. The "willing suspension of disbelief" is repeatedly lost, and the characters become people on a stage until their roles are reestablished.

Perhaps it's the pace, which through much of the first act is a quarter-beat too slow, giving too much weight to lines that ought to fly like sparks. The overlong pauses tend to give them the force of drama where the brittleness of farce is wanted.

Again and again, however, just when a passaage verges on the tedious, Ruby Holbrook picks up the scene and brings down the house with her marvelous maunderings and significant glances as the shrewd but semi-senile Dora Bunner. Holbrook's command of her character and of the state is such that she can turn her face to the backdrop and steal a scene with her shoulders.

James Secrest, as Inspector Craddock, suffers by comparison. Although energetic and engaging, he uses several accents, sometimes in the same sentence, and has a distracting array of Peter Falk mannerisms hardly appropriate to an English country sleuth.

The young people's parts are performed somewhat uncertainly, but then, Christie's young people are always uncertainly drawn. Their function is to provide misdirection and menace, which abound in "A Murder Is Announced." Their machinations would be hopelessly confusing if they did not revolve around the performances of June Hansen as Letitia Blacklock and Pauline Flanagan as Miss Marple. If anything, Hansen and Flanagan bring too much authority to their roles, like Keystone Kops shooting real bullets.

The lapses in the play are small, but they are frequent; such a classy cast should be able to fine-tune them out.