MURDER AT THE VICARAGE by Moie Charles and Barbara Toy, from the novel by Agatha Christie. Directed by Leo Brady; scenic design by Joseph St. Germain; constumes by Mary Ann Powell; lighting by James D. Waring.

With Bernie McInerney, Rudolph Willrich, Pat Karpen, George Taylor, Virginia Mattis, Mikel Lambert, J. Robert Dietz, Nancy Nichols, Arlene Stern, Robert Zuckerman, Brigid Cleary, Joseph P. Normie Jr. and Brian O'Connor.

At Olney Theatre thruogh June 24.

During Tuesday night's intermission at the Olney Theatre, one topic of conversation dominated. Whatever else the patrons may have thought of Act One, their curiosity had at least been mildly roused. Who had killed the neighborhood tyrant, Colonel Protheroe? Who - in short - dunit?

Was it the colonel's wife, anxious for her freedom? Or his slinky daughter, barred from posing in her bathing suit? Or the playboy painter for whom the daugther had hoped to pose? Or the curate, who (as the colonel had discovered) was rifling the church funds? Or the vicar? Or the vicar's wife? Or Miss Marple, town snoop?

Or was it perhaps Hercule Poirot? Poirot is not actually a character in this tale, but one never knows to what lengths Agatha Christie will go in her desire to divert us.

Whoever, all seemed reasonably right with the world and with Olney's production of "Murder at the Vicarage" in the warm night air between Acts One and Two.

The Olney ensemble, with a few slightly overwrought exceptions, had given us a series of aggressively etched portraits of rural English sterotypes - the sorts who find it perfectly natural to mutter remarks like "Nasty business!" of "I'm off!" or the inevitable "The colonel had many enemies."

Greater theater? Well, er, ah, uhh - perhaps not. But certainly a tolerable limbering-up exercise for the more strenuous work ahead on the Olney summer calendar.

But in Act Two, when the characters began to unveil, as Christie's characters will, the various secrets that had caused them to lie through their teeth in Act One, the suspense became tinged with confusion - not only, alas, the confusion Christie meant to put there, but the confusion of actors unable to remember their lines.

It is not hard to understand why Viriginia Mattis, as Miss Marple, might lose her bearings, since it falls to her to resolve most of the murky details of this plot. And it is an unusually murky pl.

As usual, everyone has a motive. There is the usual conspiracy to get as many of the suspects as possible on-stage at once, with the usual disregard for all the fundamentals of police prodcedure. Scotland Yard's man on the case seems utterly oblivious to the principle of trying to interview witnesses separately, so as to prevent them from synchronizing their stories. Not for nothing is he named "Inspector Slack."

"Murder at the Vicarage," truth to tell, seems to be one of Christie's lesser efforts, if any of them can be called lesser.

In Moie Charles' and Barbara Toy's stage adaptation, the central character, the vicar, has scarcely any connection to the real meat of the story. So Bernie McInerney's performance, full of quiet force and feeling, is more a personal triumph over the surrounding disarray than a material contribution to the show as a whole.

But from what McInerney and his colleagues did show, they look like actors it will be a pleasure to watch - after a few more performances of this creaky vehicle or, better yet, after they move on to something else.