"The Bat" gets underway with a burst of thunder that sounds like a microphone being rubbed against a cheese-grater.

This is funny thunder. Like all the melodramatic rigmarole in Mary Roberts Rinehart's and Avery Hopwood's 1920 whodunit, now at the Olney Theater, the thunder is played to the hokey hilt. And the human beings, thanks to a company of 10 capable actors under the command of director Leo Brady, are as extravagantly portrayed as the special effects.

The play was Rinehart's first and most lucrative attempt to put her brand of domestic detective story on the stage. Sixty years later, it is hard to judge just how seriously she and her collaborator expected the plot to be taken, but few of today's theater-goers will object to the Olney team's decision to play for laughs anything that can possibly be played that way.

"The Bat" involves a wealthy spinster, Cornelia Van Gorder, who rents the Long Island summer home of a dead banker, and rapidly discovers the following: The banker's bank was robbed just before his death. A large sum of money is missing. Strange people are trying to break into the house and/or scare the new tenants out. The prime suspect in the bank robbery, the cashier, is secretly engaged to Miss Van Gorder's niece and has moved into the house as the gardner. An international thief known as "The Bat" may be in the neighborhood. Somewhere in the house is a "hidden room."

You can take it from there. You can also leave it -- but at the cost of missing Pauline Flanagan's supremely haughty snooping as Miss Van Gorder, Jean Schertler's inspiring imitation of Zasu Pitts as Flanagans housekeeper/companion, Pat Karpen's utterly straight-faced gasps of terror as the niece, and Frank A. Buscaglio's shady maneuvers as a Japanese butler (made to appear so by a pair of frosted glasses designed to turn western eyes into oriental).

For all the comic embellishments, there are times when "The Bat" wants to be taken seriously, and needs nothing so much as to be sent back to its bat cave. The final curtain, for example, while it falls quite nicely, falls about 15 minutes after the event begins to seem timely. But every bat, after all, has those periods when its radar goes on the blink.